Release: 2.0.27 | Release Date: February 13, 2024

# SQLAlchemy 2.0 Documentation

# Association Proxy

`associationproxy` is used to create a read/write view of a target attribute across a relationship. It essentially conceals the usage of a “middle” attribute between two endpoints, and can be used to cherry-pick fields from both a collection of related objects or scalar relationship. or to reduce the verbosity of using the association object pattern. Applied creatively, the association proxy allows the construction of sophisticated collections and dictionary views of virtually any geometry, persisted to the database using standard, transparently configured relational patterns.

## Simplifying Scalar Collections

Consider a many-to-many mapping between two classes, `User` and `Keyword`. Each `User` can have any number of `Keyword` objects, and vice-versa (the many-to-many pattern is described at Many To Many). The example below illustrates this pattern in the same way, with the exception of an extra attribute added to the `User` class called `User.keywords`:

    from __future__ import annotations

    from typing import Final
    from typing import List

    from sqlalchemy import Column
    from sqlalchemy import ForeignKey
    from sqlalchemy import Integer
    from sqlalchemy import String
    from sqlalchemy import Table
    from sqlalchemy.orm import DeclarativeBase
    from sqlalchemy.orm import Mapped
    from sqlalchemy.orm import mapped_column
    from sqlalchemy.orm import relationship
    from sqlalchemy.ext.associationproxy import association_proxy
    from sqlalchemy.ext.associationproxy import AssociationProxy

    class Base(DeclarativeBase):
        pass

    class User(Base):
        __tablename__ = "user"
        id: Mapped[int] = mapped_column(primary_key=True)
        name: Mapped[str] = mapped_column(String(64))
        kw: Mapped[List[Keyword]] = relationship(secondary=lambda: user_keyword_table)

        def __init__(self, name: str):
            self.name = name

        # proxy the 'keyword' attribute from the 'kw' relationship
        keywords: AssociationProxy[List[str]] = association_proxy("kw", "keyword")

    class Keyword(Base):
        __tablename__ = "keyword"
        id: Mapped[int] = mapped_column(primary_key=True)
        keyword: Mapped[str] = mapped_column(String(64))

        def __init__(self, keyword: str):
            self.keyword = keyword

    user_keyword_table: Final[Table] = Table(
        "user_keyword",
        Base.metadata,
        Column("user_id", Integer, ForeignKey("user.id"), primary_key=True),
        Column("keyword_id", Integer, ForeignKey("keyword.id"), primary_key=True),
    )

In the above example, `association_proxy()` is applied to the `User` class to produce a “view” of the `kw` relationship, which exposes the string value of `.keyword` associated with each `Keyword` object. It also creates new `Keyword` objects transparently when strings are added to the collection:

    >>> user = User("jek")
    >>> user.keywords.append("cheese-inspector")
    >>> user.keywords.append("snack-ninja")
    >>> print(user.keywords)
    ['cheese-inspector', 'snack-ninja']

To understand the mechanics of this, first review the behavior of `User` and `Keyword` without using the `.keywords` association proxy. Normally, reading and manipulating the collection of “keyword” strings associated with `User` requires traversal from each collection element to the `.keyword` attribute, which can be awkward. The example below illustrates the identical series of operations applied without using the association proxy:

    >>> # identical operations without using the association proxy
    >>> user = User("jek")
    >>> user.kw.append(Keyword("cheese-inspector"))
    >>> user.kw.append(Keyword("snack-ninja"))
    >>> print([keyword.keyword for keyword in user.kw])
    ['cheese-inspector', 'snack-ninja']

The `AssociationProxy` object produced by the `association_proxy()` function is an instance of a Python descriptor, and is not considered to be “mapped” by the `Mapper` in any way. Therefore, it’s always indicated inline within the class definition of the mapped class, regardless of whether Declarative or Imperative mappings are used.

The proxy functions by operating upon the underlying mapped attribute or collection in response to operations, and changes made via the proxy are immediately apparent in the mapped attribute, as well as vice versa. The underlying attribute remains fully accessible.

When first accessed, the association proxy performs introspection operations on the target collection so that its behavior corresponds correctly. Details such as if the locally proxied attribute is a collection (as is typical) or a scalar reference, as well as if the collection acts like a set, list, or dictionary is taken into account, so that the proxy should act just like the underlying collection or attribute does.

### Creation of New Values

When a list `append()` event (or set `add()`, dictionary `__setitem__()`, or scalar assignment event) is intercepted by the association proxy, it instantiates a new instance of the “intermediary” object using its constructor, passing as a single argument the given value. In our example above, an operation like:

    user.keywords.append("cheese-inspector")

Is translated by the association proxy into the operation:

    user.kw.append(Keyword("cheese-inspector"))

The example works here because we have designed the constructor for `Keyword` to accept a single positional argument, `keyword`. For those cases where a single-argument constructor isn’t feasible, the association proxy’s creational behavior can be customized using the `association_proxy.creator` argument, which references a callable (i.e. Python function) that will produce a new object instance given the singular argument. Below we illustrate this using a lambda as is typical:

    class User(Base):
        ...

        # use Keyword(keyword=kw) on append() events
        keywords: AssociationProxy[List[str]] = association_proxy(
            "kw", "keyword", creator=lambda kw: Keyword(keyword=kw)
        )

The `creator` function accepts a single argument in the case of a list- or set- based collection, or a scalar attribute. In the case of a dictionary-based collection, it accepts two arguments, “key” and “value”. An example of this is below in Proxying to Dictionary Based Collections.

## Simplifying Association Objects

The “association object” pattern is an extended form of a many-to-many relationship, and is described at Association Object. Association proxies are useful for keeping “association objects” out of the way during regular use.

Suppose our `user_keyword` table above had additional columns which we’d like to map explicitly, but in most cases we don’t require direct access to these attributes. Below, we illustrate a new mapping which introduces the `UserKeywordAssociation` class, which is mapped to the `user_keyword` table illustrated earlier. This class adds an additional column `special_key`, a value which we occasionally want to access, but not in the usual case. We create an association proxy on the `User` class called `keywords`, which will bridge the gap from the `user_keyword_associations` collection of `User` to the `.keyword` attribute present on each `UserKeywordAssociation`:

    from __future__ import annotations

    from typing import List
    from typing import Optional

    from sqlalchemy import ForeignKey
    from sqlalchemy import String
    from sqlalchemy.ext.associationproxy import association_proxy
    from sqlalchemy.ext.associationproxy import AssociationProxy
    from sqlalchemy.orm import DeclarativeBase
    from sqlalchemy.orm import Mapped
    from sqlalchemy.orm import mapped_column
    from sqlalchemy.orm import relationship

    class Base(DeclarativeBase):
        pass

    class User(Base):
        __tablename__ = "user"

        id: Mapped[int] = mapped_column(primary_key=True)
        name: Mapped[str] = mapped_column(String(64))

        user_keyword_associations: Mapped[List[UserKeywordAssociation]] = relationship(
            back_populates="user",
            cascade="all, delete-orphan",
        )

        # association proxy of "user_keyword_associations" collection
        # to "keyword" attribute
        keywords: AssociationProxy[List[Keyword]] = association_proxy(
            "user_keyword_associations",
            "keyword",
            creator=lambda keyword_obj: UserKeywordAssociation(keyword=keyword_obj),
        )

        def __init__(self, name: str):
            self.name = name

    class UserKeywordAssociation(Base):
        __tablename__ = "user_keyword"
        user_id: Mapped[int] = mapped_column(ForeignKey("user.id"), primary_key=True)
        keyword_id: Mapped[int] = mapped_column(ForeignKey("keyword.id"), primary_key=True)
        special_key: Mapped[Optional[str]] = mapped_column(String(50))

        user: Mapped[User] = relationship(back_populates="user_keyword_associations")

        keyword: Mapped[Keyword] = relationship()

    class Keyword(Base):
        __tablename__ = "keyword"
        id: Mapped[int] = mapped_column(primary_key=True)
        keyword: Mapped[str] = mapped_column("keyword", String(64))

        def __init__(self, keyword: str):
            self.keyword = keyword

        def __repr__(self) -> str:
            return f"Keyword({self.keyword!r})"

With the above configuration, we can operate upon the `.keywords` collection of each `User` object, each of which exposes a collection of `Keyword` objects that are obtained from the underlying `UserKeywordAssociation` elements:

    >>> user = User("log")
    >>> for kw in (Keyword("new_from_blammo"), Keyword("its_big")):
    ...     user.keywords.append(kw)
    >>> print(user.keywords)
    [Keyword('new_from_blammo'), Keyword('its_big')]

This example is in contrast to the example illustrated previously at Simplifying Scalar Collections, where the association proxy exposed a collection of strings, rather than a collection of composed objects. In this case, each `.keywords.append()` operation is equivalent to:

    >>> user.user_keyword_associations.append(
    ...     UserKeywordAssociation(keyword=Keyword("its_heavy"))
    ... )

The `UserKeywordAssociation` object has two attributes that are both populated within the scope of the `append()` operation of the association proxy; `.keyword`, which refers to the `Keyword` object, and `.user`, which refers to the `User` object. The `.keyword` attribute is populated first, as the association proxy generates a new `UserKeywordAssociation` object in response to the `.append()` operation, assigning the given `Keyword` instance to the `.keyword` attribute. Then, as the `UserKeywordAssociation` object is appended to the `User.user_keyword_associations` collection, the `UserKeywordAssociation.user` attribute, configured as `back_populates` for `User.user_keyword_associations`, is initialized upon the given `UserKeywordAssociation` instance to refer to the parent `User` receiving the append operation. The `special_key` argument above is left at its default value of `None`.

For those cases where we do want `special_key` to have a value, we create the `UserKeywordAssociation` object explicitly. Below we assign all three attributes, wherein the assignment of `.user` during construction, has the effect of appending the new `UserKeywordAssociation` to the `User.user_keyword_associations` collection (via the relationship):

    >>> UserKeywordAssociation(
    ...     keyword=Keyword("its_wood"), user=user, special_key="my special key"
    ... )

The association proxy returns to us a collection of `Keyword` objects represented by all these operations:

    >>> print(user.keywords)
    [Keyword('new_from_blammo'), Keyword('its_big'), Keyword('its_heavy'), Keyword('its_wood')]

## Proxying to Dictionary Based Collections

The association proxy can proxy to dictionary based collections as well. SQLAlchemy mappings usually use the `attribute_keyed_dict()` collection type to create dictionary collections, as well as the extended techniques described in Custom Dictionary-Based Collections.

The association proxy adjusts its behavior when it detects the usage of a dictionary-based collection. When new values are added to the dictionary, the association proxy instantiates the intermediary object by passing two arguments to the creation function instead of one, the key and the value. As always, this creation function defaults to the constructor of the intermediary class, and can be customized using the `creator` argument.

Below, we modify our `UserKeywordAssociation` example such that the `User.user_keyword_associations` collection will now be mapped using a dictionary, where the `UserKeywordAssociation.special_key` argument will be used as the key for the dictionary. We also apply a `creator` argument to the `User.keywords` proxy so that these values are assigned appropriately when new elements are added to the dictionary:

    from __future__ import annotations
    from typing import Dict

    from sqlalchemy import ForeignKey
    from sqlalchemy import String
    from sqlalchemy.ext.associationproxy import association_proxy
    from sqlalchemy.ext.associationproxy import AssociationProxy
    from sqlalchemy.orm import DeclarativeBase
    from sqlalchemy.orm import Mapped
    from sqlalchemy.orm import mapped_column
    from sqlalchemy.orm import relationship
    from sqlalchemy.orm.collections import attribute_keyed_dict

    class Base(DeclarativeBase):
        pass

    class User(Base):
        __tablename__ = "user"
        id: Mapped[int] = mapped_column(primary_key=True)
        name: Mapped[str] = mapped_column(String(64))

        # user/user_keyword_associations relationship, mapping
        # user_keyword_associations with a dictionary against "special_key" as key.
        user_keyword_associations: Mapped[Dict[str, UserKeywordAssociation]] = relationship(
            back_populates="user",
            collection_class=attribute_keyed_dict("special_key"),
            cascade="all, delete-orphan",
        )
        # proxy to 'user_keyword_associations', instantiating
        # UserKeywordAssociation assigning the new key to 'special_key',
        # values to 'keyword'.
        keywords: AssociationProxy[Dict[str, Keyword]] = association_proxy(
            "user_keyword_associations",
            "keyword",
            creator=lambda k, v: UserKeywordAssociation(special_key=k, keyword=v),
        )

        def __init__(self, name: str):
            self.name = name

    class UserKeywordAssociation(Base):
        __tablename__ = "user_keyword"
        user_id: Mapped[int] = mapped_column(ForeignKey("user.id"), primary_key=True)
        keyword_id: Mapped[int] = mapped_column(ForeignKey("keyword.id"), primary_key=True)
        special_key: Mapped[str]

        user: Mapped[User] = relationship(
            back_populates="user_keyword_associations",
        )
        keyword: Mapped[Keyword] = relationship()

    class Keyword(Base):
        __tablename__ = "keyword"
        id: Mapped[int] = mapped_column(primary_key=True)
        keyword: Mapped[str] = mapped_column(String(64))

        def __init__(self, keyword: str):
            self.keyword = keyword

        def __repr__(self) -> str:
            return f"Keyword({self.keyword!r})"

We illustrate the `.keywords` collection as a dictionary, mapping the `UserKeywordAssociation.special_key` value to `Keyword` objects:

    >>> user = User("log")

    >>> user.keywords["sk1"] = Keyword("kw1")
    >>> user.keywords["sk2"] = Keyword("kw2")

    >>> print(user.keywords)
    {'sk1': Keyword('kw1'), 'sk2': Keyword('kw2')}

## Composite Association Proxies

Given our previous examples of proxying from relationship to scalar attribute, proxying across an association object, and proxying dictionaries, we can combine all three techniques together to give `User` a `keywords` dictionary that deals strictly with the string value of `special_key` mapped to the string `keyword`. Both the `UserKeywordAssociation` and `Keyword` classes are entirely concealed. This is achieved by building an association proxy on `User` that refers to an association proxy present on `UserKeywordAssociation`:

    from __future__ import annotations

    from sqlalchemy import ForeignKey
    from sqlalchemy import String
    from sqlalchemy.ext.associationproxy import association_proxy
    from sqlalchemy.ext.associationproxy import AssociationProxy
    from sqlalchemy.orm import DeclarativeBase
    from sqlalchemy.orm import Mapped
    from sqlalchemy.orm import mapped_column
    from sqlalchemy.orm import relationship
    from sqlalchemy.orm.collections import attribute_keyed_dict

    class Base(DeclarativeBase):
        pass

    class User(Base):
        __tablename__ = "user"
        id: Mapped[int] = mapped_column(primary_key=True)
        name: Mapped[str] = mapped_column(String(64))

        user_keyword_associations: Mapped[Dict[str, UserKeywordAssociation]] = relationship(
            back_populates="user",
            collection_class=attribute_keyed_dict("special_key"),
            cascade="all, delete-orphan",
        )
        # the same 'user_keyword_associations'->'keyword' proxy as in
        # the basic dictionary example.
        keywords: AssociationProxy[Dict[str, str]] = association_proxy(
            "user_keyword_associations",
            "keyword",
            creator=lambda k, v: UserKeywordAssociation(special_key=k, keyword=v),
        )

        def __init__(self, name: str):
            self.name = name

    class UserKeywordAssociation(Base):
        __tablename__ = "user_keyword"
        user_id: Mapped[int] = mapped_column(ForeignKey("user.id"), primary_key=True)
        keyword_id: Mapped[int] = mapped_column(ForeignKey("keyword.id"), primary_key=True)
        special_key: Mapped[str] = mapped_column(String(64))
        user: Mapped[User] = relationship(
            back_populates="user_keyword_associations",
        )

        # the relationship to Keyword is now called
        # 'kw'
        kw: Mapped[Keyword] = relationship()

        # 'keyword' is changed to be a proxy to the
        # 'keyword' attribute of 'Keyword'
        keyword: AssociationProxy[Dict[str, str]] = association_proxy("kw", "keyword")

    class Keyword(Base):
        __tablename__ = "keyword"
        id: Mapped[int] = mapped_column(primary_key=True)
        keyword: Mapped[str] = mapped_column(String(64))

        def __init__(self, keyword: str):
            self.keyword = keyword

`User.keywords` is now a dictionary of string to string, where `UserKeywordAssociation` and `Keyword` objects are created and removed for us transparently using the association proxy. In the example below, we illustrate usage of the assignment operator, also appropriately handled by the association proxy, to apply a dictionary value to the collection at once:

    >>> user = User("log")
    >>> user.keywords = {"sk1": "kw1", "sk2": "kw2"}
    >>> print(user.keywords)
    {'sk1': 'kw1', 'sk2': 'kw2'}

    >>> user.keywords["sk3"] = "kw3"
    >>> del user.keywords["sk2"]
    >>> print(user.keywords)
    {'sk1': 'kw1', 'sk3': 'kw3'}

    >>> # illustrate un-proxied usage
    ... print(user.user_keyword_associations["sk3"].kw)
    <__main__.Keyword object at 0x12ceb90>

One caveat with our example above is that because `Keyword` objects are created for each dictionary set operation, the example fails to maintain uniqueness for the `Keyword` objects on their string name, which is a typical requirement for a tagging scenario such as this one. For this use case the recipe UniqueObject, or a comparable creational strategy, is recommended, which will apply a “lookup first, then create” strategy to the constructor of the `Keyword` class, so that an already existing `Keyword` is returned if the given name is already present.

## Querying with Association Proxies

The `AssociationProxy` features simple SQL construction capabilities which work at the class level in a similar way as other ORM-mapped attributes, and provide rudimentary filtering support primarily based on the SQL `EXISTS` keyword.

Note

The primary purpose of the association proxy extension is to allow for improved persistence and object-access patterns with mapped object instances that are already loaded. The class-bound querying feature is of limited use and will not replace the need to refer to the underlying attributes when constructing SQL queries with JOINs, eager loading options, etc.

For this section, assume a class with both an association proxy that refers to a column, as well as an association proxy that refers to a related object, as in the example mapping below:

    from __future__ import annotations
    from sqlalchemy import Column, ForeignKey, Integer, String
    from sqlalchemy.ext.associationproxy import association_proxy, AssociationProxy
    from sqlalchemy.orm import DeclarativeBase, relationship
    from sqlalchemy.orm.collections import attribute_keyed_dict
    from sqlalchemy.orm.collections import Mapped

    class Base(DeclarativeBase):
        pass

    class User(Base):
        __tablename__ = "user"
        id: Mapped[int] = mapped_column(primary_key=True)
        name: Mapped[str] = mapped_column(String(64))

        user_keyword_associations: Mapped[UserKeywordAssociation] = relationship(
            cascade="all, delete-orphan",
        )

        # object-targeted association proxy
        keywords: AssociationProxy[List[Keyword]] = association_proxy(
            "user_keyword_associations",
            "keyword",
        )

        # column-targeted association proxy
        special_keys: AssociationProxy[List[str]] = association_proxy(
            "user_keyword_associations", "special_key"
        )

    class UserKeywordAssociation(Base):
        __tablename__ = "user_keyword"
        user_id: Mapped[int] = mapped_column(ForeignKey("user.id"), primary_key=True)
        keyword_id: Mapped[int] = mapped_column(ForeignKey("keyword.id"), primary_key=True)
        special_key: Mapped[str] = mapped_column(String(64))
        keyword: Mapped[Keyword] = relationship()

    class Keyword(Base):
        __tablename__ = "keyword"
        id: Mapped[int] = mapped_column(primary_key=True)
        keyword: Mapped[str] = mapped_column(String(64))

The SQL generated takes the form of a correlated subquery against the EXISTS SQL operator so that it can be used in a WHERE clause without the need for additional modifications to the enclosing query. If the immediate target of an association proxy is a mapped column expression, standard column operators can be used which will be embedded in the subquery. For example a straight equality operator:

    >>> print(session.scalars(select(User).where(User.special_keys == "jek")))
    SELECT "user".id AS user_id, "user".name AS user_name
    FROM "user"
    WHERE EXISTS (SELECT 1
    FROM user_keyword
    WHERE "user".id = user_keyword.user_id AND user_keyword.special_key = :special_key_1)

a LIKE operator:

    >>> print(session.scalars(select(User).where(User.special_keys.like("%jek"))))
    SELECT "user".id AS user_id, "user".name AS user_name
    FROM "user"
    WHERE EXISTS (SELECT 1
    FROM user_keyword
    WHERE "user".id = user_keyword.user_id AND user_keyword.special_key LIKE :special_key_1)

For association proxies where the immediate target is a related object or collection, or another association proxy or attribute on the related object, relationship-oriented operators can be used instead, such as `PropComparator.has()` and `PropComparator.any()`. The `User.keywords` attribute is in fact two association proxies linked together, so when using this proxy for generating SQL phrases, we get two levels of EXISTS subqueries:

    >>> print(session.scalars(select(User).where(User.keywords.any(Keyword.keyword == "jek"))))
    SELECT "user".id AS user_id, "user".name AS user_name
    FROM "user"
    WHERE EXISTS (SELECT 1
    FROM user_keyword
    WHERE "user".id = user_keyword.user_id AND (EXISTS (SELECT 1
    FROM keyword
    WHERE keyword.id = user_keyword.keyword_id AND keyword.keyword = :keyword_1)))

This is not the most efficient form of SQL, so while association proxies can be convenient for generating WHERE criteria quickly, SQL results should be inspected and “unrolled” into explicit JOIN criteria for best use, especially when chaining association proxies together.

Changed in version 1.3: Association proxy features distinct querying modes based on the type of target. See AssociationProxy now provides standard column operators for a column-oriented target.

## Cascading Scalar Deletes

New in version 1.3.

Given a mapping as:

    from __future__ import annotations
    from sqlalchemy import Column, ForeignKey, Integer, String
    from sqlalchemy.ext.associationproxy import association_proxy, AssociationProxy
    from sqlalchemy.orm import DeclarativeBase, relationship
    from sqlalchemy.orm.collections import attribute_keyed_dict
    from sqlalchemy.orm.collections import Mapped

    class Base(DeclarativeBase):
        pass

    class A(Base):
        __tablename__ = "test_a"
        id: Mapped[int] = mapped_column(primary_key=True)
        ab: Mapped[AB] = relationship(uselist=False)
        b: AssociationProxy[B] = association_proxy(
            "ab", "b", creator=lambda b: AB(b=b), cascade_scalar_deletes=True
        )

    class B(Base):
        __tablename__ = "test_b"
        id: Mapped[int] = mapped_column(primary_key=True)

    class AB(Base):
        __tablename__ = "test_ab"
        a_id: Mapped[int] = mapped_column(ForeignKey(A.id), primary_key=True)
        b_id: Mapped[int] = mapped_column(ForeignKey(B.id), primary_key=True)

        b: Mapped[B] = relationship()

An assignment to `A.b` will generate an `AB` object:

    a.b = B()

The `A.b` association is scalar, and includes use of the parameter `AssociationProxy.cascade_scalar_deletes`. When this parameter is enabled, setting `A.b` to `None` will remove `A.ab` as well:

    a.b = None
    assert a.ab is None

When `AssociationProxy.cascade_scalar_deletes` is not set, the association object `a.ab` above would remain in place.

Note that this is not the behavior for collection-based association proxies; in that case, the intermediary association object is always removed when members of the proxied collection are removed. Whether or not the row is deleted depends on the relationship cascade setting.

See also

Cascades

## Scalar Relationships

The example below illustrates the use of the association proxy on the many side of of a one-to-many relationship, accessing attributes of a scalar object:

    from __future__ import annotations

    from typing import List

    from sqlalchemy import ForeignKey
    from sqlalchemy import String
    from sqlalchemy.ext.associationproxy import association_proxy
    from sqlalchemy.ext.associationproxy import AssociationProxy
    from sqlalchemy.orm import DeclarativeBase
    from sqlalchemy.orm import Mapped
    from sqlalchemy.orm import mapped_column
    from sqlalchemy.orm import relationship

    class Base(DeclarativeBase):
        pass

    class Recipe(Base):
        __tablename__ = "recipe"
        id: Mapped[int] = mapped_column(primary_key=True)
        name: Mapped[str] = mapped_column(String(64))

        steps: Mapped[List[Step]] = relationship(back_populates="recipe")
        step_descriptions: AssociationProxy[List[str]] = association_proxy(
            "steps", "description"
        )

    class Step(Base):
        __tablename__ = "step"
        id: Mapped[int] = mapped_column(primary_key=True)
        description: Mapped[str]
        recipe_id: Mapped[int] = mapped_column(ForeignKey("recipe.id"))
        recipe: Mapped[Recipe] = relationship(back_populates="steps")

        recipe_name: AssociationProxy[str] = association_proxy("recipe", "name")

        def __init__(self, description: str) -> None:
            self.description = description

    my_snack = Recipe(
        name="afternoon snack",
        step_descriptions=[
            "slice bread",
            "spread peanut butted",
            "eat sandwich",
        ],
    )

A summary of the steps of `my_snack` can be printed using:

    >>> for i, step in enumerate(my_snack.steps, 1):
    ...     print(f"Step {i} of {step.recipe_name!r}: {step.description}")
    Step 1 of 'afternoon snack': slice bread
    Step 2 of 'afternoon snack': spread peanut butted
    Step 3 of 'afternoon snack': eat sandwich

## API Documentation

Object Name | Description
--- | ---
association_proxy(target_collection, attr, *, [creator, getset_factory, proxy_factory, proxy_bulk_set, info, cascade_scalar_deletes, create_on_none_assignment, init, repr, default, default_factory, compare, kw_only]) | Return a Python property implementing a view of a target attribute which references an attribute on members of the target.
AssociationProxy | A descriptor that presents a read/write view of an object attribute.
AssociationProxyExtensionType | An enumeration.
AssociationProxyInstance | A per-class object that serves class- and object-specific results.
ColumnAssociationProxyInstance | an `AssociationProxyInstance` that has a database column as a target.
ObjectAssociationProxyInstance | an `AssociationProxyInstance` that has an object as a target.

function sqlalchemy.ext.associationproxy.association_proxy(target_collection: str, attr: str, *, creator: _CreatorProtocol | None = None, getset_factory: _GetSetFactoryProtocol | None = None, proxy_factory: _ProxyFactoryProtocol | None = None, proxy_bulk_set: _ProxyBulkSetProtocol | None = None, info: _InfoType | None = None, cascade_scalar_deletes: bool = False, create_on_none_assignment: bool = False, init: _NoArg | bool = _NoArg.NO_ARG, repr: _NoArg | bool = _NoArg.NO_ARG, default: Any | None = _NoArg.NO_ARG, default_factory: _NoArg | Callable[[], _T] = _NoArg.NO_ARG, compare: _NoArg | bool = _NoArg.NO_ARG, kw_only: _NoArg | bool = _NoArg.NO_ARG) → AssociationProxy[Any]

  Return a Python property implementing a view of a target attribute which references an attribute on members of the target.

  The returned value is an instance of `AssociationProxy`.

  Implements a Python property representing a relationship as a collection of simpler values, or a scalar value. The proxied property will mimic the collection type of the target (list, dict or set), or, in the case of a one to one relationship, a simple scalar value.

  Parameters:

    - target_collection – Name of the attribute that is the immediate target. This attribute is typically mapped by `relationship()` to link to a target collection, but can also be a many-to-one or non-scalar relationship.

    - attr – Attribute on the associated instance or instances that are available on instances of the target object.

    - creator –

      optional.

      Defines custom behavior when new items are added to the proxied collection.

      By default, adding new items to the collection will trigger a construction of an instance of the target object, passing the given item as a positional argument to the target constructor. For cases where this isn’t sufficient, `association_proxy.creator` can supply a callable that will construct the object in the appropriate way, given the item that was passed.

      For list- and set- oriented collections, a single argument is passed to the callable. For dictionary oriented collections, two arguments are passed, corresponding to the key and value.

      The `association_proxy.creator` callable is also invoked for scalar (i.e. many-to-one, one-to-one) relationships. If the current value of the target relationship attribute is `None`, the callable is used to construct a new object. If an object value already exists, the given attribute value is populated onto that object.

      See also

      Creation of New Values

    - cascade_scalar_deletes –

      when True, indicates that setting the proxied value to `None`, or deleting it via `del`, should also remove the source object. Only applies to scalar attributes. Normally, removing the proxied target will not remove the proxy source, as this object may have other state that is still to be kept.

      New in version 1.3.

      See also

      Cascading Scalar Deletes - complete usage example

    - create_on_none_assignment –

      when True, indicates that setting the proxied value to `None` should create the source object if it does not exist, using the creator. Only applies to scalar attributes. This is mutually exclusive vs. the `assocation_proxy.cascade_scalar_deletes`.

      New in version 2.0.18.

    - init –

      Specific to Declarative Dataclass Mapping, specifies if the mapped attribute should be part of the `__init__()` method as generated by the dataclass process.

      New in version 2.0.0b4.

    - repr –

      Specific to Declarative Dataclass Mapping, specifies if the attribute established by this `AssociationProxy` should be part of the `__repr__()` method as generated by the dataclass process.

      New in version 2.0.0b4.

    - default_factory –

      Specific to Declarative Dataclass Mapping, specifies a default-value generation function that will take place as part of the `__init__()` method as generated by the dataclass process.

      New in version 2.0.0b4.

    - compare –

      Specific to Declarative Dataclass Mapping, indicates if this field should be included in comparison operations when generating the `__eq__()` and `__ne__()` methods for the mapped class.

      New in version 2.0.0b4.

    - kw_only –

      Specific to Declarative Dataclass Mapping, indicates if this field should be marked as keyword-only when generating the `__init__()` method as generated by the dataclass process.

      New in version 2.0.0b4.

    - info – optional, will be assigned to `AssociationProxy.info` if present.

  The following additional parameters involve injection of custom behaviors within the `AssociationProxy` object and are for advanced use only:

  Parameters:

    - getset_factory –

      Optional. Proxied attribute access is automatically handled by routines that get and set values based on the attr argument for this proxy.

      If you would like to customize this behavior, you may supply a getset_factory callable that produces a tuple of getter and setter functions. The factory is called with two arguments, the abstract type of the underlying collection and this proxy instance.

    - proxy_factory – Optional. The type of collection to emulate is determined by sniffing the target collection. If your collection type can’t be determined by duck typing or you’d like to use a different collection implementation, you may supply a factory function to produce those collections. Only applicable to non-scalar relationships.

    - proxy_bulk_set – Optional, use with proxy_factory.

class sqlalchemy.ext.associationproxy.AssociationProxy

  A descriptor that presents a read/write view of an object attribute.

  Members

  __init__(), cascade_scalar_deletes, create_on_none_assignment, creator, extension_type, for_class(), getset_factory, info, is_aliased_class, is_attribute, is_bundle, is_clause_element, is_instance, is_mapper, is_property, is_selectable, key, proxy_bulk_set, proxy_factory, target_collection, value_attr

  Class signature

  class `sqlalchemy.ext.associationproxy.AssociationProxy` (`sqlalchemy.orm.base.InspectionAttrInfo`, `sqlalchemy.orm.base.ORMDescriptor`, `sqlalchemy.orm._DCAttributeOptions`, `sqlalchemy.ext.associationproxy._AssociationProxyProtocol`)

  method `sqlalchemy.ext.associationproxy.AssociationProxy.`__init__(target_collection: str, attr: str, *, creator: _CreatorProtocol | None = None, getset_factory: _GetSetFactoryProtocol | None = None, proxy_factory: _ProxyFactoryProtocol | None = None, proxy_bulk_set: _ProxyBulkSetProtocol | None = None, info: _InfoType | None = None, cascade_scalar_deletes: bool = False, create_on_none_assignment: bool = False, attribute_options: _AttributeOptions | None = None)

    Construct a new `AssociationProxy`.

    The `AssociationProxy` object is typically constructed using the `association_proxy()` constructor function. See the description of `association_proxy()` for a description of all parameters.

  attribute `sqlalchemy.ext.associationproxy.AssociationProxy.`cascade_scalar_deletes: bool
  attribute `sqlalchemy.ext.associationproxy.AssociationProxy.`create_on_none_assignment: bool
  attribute `sqlalchemy.ext.associationproxy.AssociationProxy.`creator: _CreatorProtocol | None
  attribute `sqlalchemy.ext.associationproxy.AssociationProxy.`extension_type: InspectionAttrExtensionType = 'ASSOCIATION_PROXY'

    The extension type, if any. Defaults to `NotExtension.NOT_EXTENSION`

    See also

    `HybridExtensionType`

    `AssociationProxyExtensionType`

  method `sqlalchemy.ext.associationproxy.AssociationProxy.`for_class(class_: Type[Any], obj: object | None = None) → AssociationProxyInstance[_T]

    Return the internal state local to a specific mapped class.

    E.g., given a class `User`:

        class User(Base):
            # ...

            keywords = association_proxy('kws', 'keyword')

    If we access this `AssociationProxy` from `Mapper.all_orm_descriptors`, and we want to view the target class for this proxy as mapped by `User`:

        inspect(User).all_orm_descriptors["keywords"].for_class(User).target_class

    This returns an instance of `AssociationProxyInstance` that is specific to the `User` class. The `AssociationProxy` object remains agnostic of its parent class.

    Parameters:

      - class_ – the class that we are returning state for.

      - obj – optional, an instance of the class that is required if the attribute refers to a polymorphic target, e.g. where we have to look at the type of the actual destination object to get the complete path.

    New in version 1.3: - `AssociationProxy` no longer stores any state specific to a particular parent class; the state is now stored in per-class `AssociationProxyInstance` objects.

  attribute `sqlalchemy.ext.associationproxy.AssociationProxy.`getset_factory: _GetSetFactoryProtocol | None
  attribute `sqlalchemy.ext.associationproxy.AssociationProxy.`info

    inherited from the `InspectionAttrInfo.info` attribute of `InspectionAttrInfo`

    Info dictionary associated with the object, allowing user-defined data to be associated with this `InspectionAttr`.

    The dictionary is generated when first accessed. Alternatively, it can be specified as a constructor argument to the `column_property()`, `relationship()`, or `composite()` functions.

    See also

    `QueryableAttribute.info`

    `SchemaItem.info`

  attribute `sqlalchemy.ext.associationproxy.AssociationProxy.`is_aliased_class = False

    inherited from the `InspectionAttr.is_aliased_class` attribute of `InspectionAttr`

    True if this object is an instance of `AliasedClass`.

  attribute `sqlalchemy.ext.associationproxy.AssociationProxy.`is_attribute = True

    True if this object is a Python descriptor.

    This can refer to one of many types. Usually a `QueryableAttribute` which handles attributes events on behalf of a `MapperProperty`. But can also be an extension type such as `AssociationProxy` or `hybrid_property`. The `InspectionAttr.extension_type` will refer to a constant identifying the specific subtype.

    See also

    `Mapper.all_orm_descriptors`

  attribute `sqlalchemy.ext.associationproxy.AssociationProxy.`is_bundle = False

    inherited from the `InspectionAttr.is_bundle` attribute of `InspectionAttr`

    True if this object is an instance of `Bundle`.

  attribute `sqlalchemy.ext.associationproxy.AssociationProxy.`is_clause_element = False

    inherited from the `InspectionAttr.is_clause_element` attribute of `InspectionAttr`

    True if this object is an instance of `ClauseElement`.

  attribute `sqlalchemy.ext.associationproxy.AssociationProxy.`is_instance = False

    inherited from the `InspectionAttr.is_instance` attribute of `InspectionAttr`

    True if this object is an instance of `InstanceState`.

  attribute `sqlalchemy.ext.associationproxy.AssociationProxy.`is_mapper = False

    inherited from the `InspectionAttr.is_mapper` attribute of `InspectionAttr`

    True if this object is an instance of `Mapper`.

  attribute `sqlalchemy.ext.associationproxy.AssociationProxy.`is_property = False

    inherited from the `InspectionAttr.is_property` attribute of `InspectionAttr`

    True if this object is an instance of `MapperProperty`.

  attribute `sqlalchemy.ext.associationproxy.AssociationProxy.`is_selectable = False

    inherited from the `InspectionAttr.is_selectable` attribute of `InspectionAttr`

    Return True if this object is an instance of `Selectable`.

  attribute `sqlalchemy.ext.associationproxy.AssociationProxy.`key: str
  attribute `sqlalchemy.ext.associationproxy.AssociationProxy.`proxy_bulk_set: _ProxyBulkSetProtocol | None
  attribute `sqlalchemy.ext.associationproxy.AssociationProxy.`proxy_factory: _ProxyFactoryProtocol | None
  attribute `sqlalchemy.ext.associationproxy.AssociationProxy.`target_collection: str
  attribute `sqlalchemy.ext.associationproxy.AssociationProxy.`value_attr: str

class sqlalchemy.ext.associationproxy.AssociationProxyInstance

  A per-class object that serves class- and object-specific results.

  This is used by `AssociationProxy` when it is invoked in terms of a specific class or instance of a class, i.e. when it is used as a regular Python descriptor.

  When referring to the `AssociationProxy` as a normal Python descriptor, the `AssociationProxyInstance` is the object that actually serves the information. Under normal circumstances, its presence is transparent:

      >>> User.keywords.scalar
      False

  In the special case that the `AssociationProxy` object is being accessed directly, in order to get an explicit handle to the `AssociationProxyInstance`, use the `AssociationProxy.for_class()` method:

      proxy_state = inspect(User).all_orm_descriptors["keywords"].for_class(User)

      # view if proxy object is scalar or not
      >>> proxy_state.scalar
      False

  New in version 1.3.

  Members

  __eq__(), __le__(), __lt__(), __ne__(), all_(), any(), any_(), asc(), attr, between(), bitwise_and(), bitwise_lshift(), bitwise_not(), bitwise_or(), bitwise_rshift(), bitwise_xor(), bool_op(), collate(), collection_class, concat(), contains(), delete(), desc(), distinct(), endswith(), for_proxy(), get(), has(), icontains(), iendswith(), ilike(), in_(), info, is_(), is_distinct_from(), is_not(), is_not_distinct_from(), isnot(), isnot_distinct_from(), istartswith(), like(), local_attr, match(), not_ilike(), not_in(), not_like(), notilike(), notin_(), notlike(), nulls_first(), nulls_last(), nullsfirst(), nullslast(), op(), operate(), parent, regexp_match(), regexp_replace(), remote_attr, reverse_operate(), scalar, set(), startswith(), target_class, timetuple

  Class signature

  class `sqlalchemy.ext.associationproxy.AssociationProxyInstance` (`sqlalchemy.orm.base.SQLORMOperations`)

  method `sqlalchemy.ext.associationproxy.AssociationProxyInstance.`__eq__(other: Any) → ColumnOperators

    inherited from the `sqlalchemy.sql.expression.ColumnOperators.__eq__` method of `ColumnOperators`

    Implement the `==` operator.

    In a column context, produces the clause `a = b`. If the target is `None`, produces `a IS NULL`.

  method `sqlalchemy.ext.associationproxy.AssociationProxyInstance.`__le__(other: Any) → ColumnOperators

    inherited from the `sqlalchemy.sql.expression.ColumnOperators.__le__` method of `ColumnOperators`

    Implement the `<=` operator.

    In a column context, produces the clause `a <= b`.

  method `sqlalchemy.ext.associationproxy.AssociationProxyInstance.`__lt__(other: Any) → ColumnOperators

    inherited from the `sqlalchemy.sql.expression.ColumnOperators.__lt__` method of `ColumnOperators`

    Implement the `<` operator.

    In a column context, produces the clause `a < b`.

  method `sqlalchemy.ext.associationproxy.AssociationProxyInstance.`__ne__(other: Any) → ColumnOperators

    inherited from the `sqlalchemy.sql.expression.ColumnOperators.__ne__` method of `ColumnOperators`

    Implement the `!=` operator.

    In a column context, produces the clause `a != b`. If the target is `None`, produces `a IS NOT NULL`.

  method `sqlalchemy.ext.associationproxy.AssociationProxyInstance.`all_() → ColumnOperators

    inherited from the `ColumnOperators.all_()` method of `ColumnOperators`

    Produce an `all_()` clause against the parent object.

    See the documentation for `all_()` for examples.

    Note

    be sure to not confuse the newer `ColumnOperators.all_()` method with the legacy version of this method, the `Comparator.all()` method that’s specific to `ARRAY`, which uses a different calling style.

  method `sqlalchemy.ext.associationproxy.AssociationProxyInstance.`any(criterion: _ColumnExpressionArgument[bool] | None = None, **kwargs: Any) → ColumnElement[bool]

    Produce a proxied ‘any’ expression using EXISTS.

    This expression will be a composed product using the `Comparator.any()` and/or `Comparator.has()` operators of the underlying proxied attributes.

  method `sqlalchemy.ext.associationproxy.AssociationProxyInstance.`any_() → ColumnOperators

    inherited from the `ColumnOperators.any_()` method of `ColumnOperators`

    Produce an `any_()` clause against the parent object.

    See the documentation for `any_()` for examples.

    Note

    be sure to not confuse the newer `ColumnOperators.any_()` method with the legacy version of this method, the `Comparator.any()` method that’s specific to `ARRAY`, which uses a different calling style.

  method `sqlalchemy.ext.associationproxy.AssociationProxyInstance.`asc() → ColumnOperators

    inherited from the `ColumnOperators.asc()` method of `ColumnOperators`

    Produce a `asc()` clause against the parent object.

  attribute `sqlalchemy.ext.associationproxy.AssociationProxyInstance.`attr

    Return a tuple of `(local_attr, remote_attr)`.

    This attribute was originally intended to facilitate using the `Query.join()` method to join across the two relationships at once, however this makes use of a deprecated calling style.

    To use `select.join()` or `Query.join()` with an association proxy, the current method is to make use of the `AssociationProxyInstance.local_attr` and `AssociationProxyInstance.remote_attr` attributes separately:

        stmt = (
            select(Parent).
            join(Parent.proxied.local_attr).
            join(Parent.proxied.remote_attr)
        )

    A future release may seek to provide a more succinct join pattern for association proxy attributes.

    See also

    `AssociationProxyInstance.local_attr`

    `AssociationProxyInstance.remote_attr`

  method `sqlalchemy.ext.associationproxy.AssociationProxyInstance.`between(cleft: Any, cright: Any, symmetric: bool = False) → ColumnOperators

    inherited from the `ColumnOperators.between()` method of `ColumnOperators`

    Produce a `between()` clause against the parent object, given the lower and upper range.

  method `sqlalchemy.ext.associationproxy.AssociationProxyInstance.`bitwise_and(other: Any) → ColumnOperators

    inherited from the `ColumnOperators.bitwise_and()` method of `ColumnOperators`

    Produce a bitwise AND operation, typically via the `&` operator.

    New in version 2.0.2.

    See also

    Bitwise Operators

  method `sqlalchemy.ext.associationproxy.AssociationProxyInstance.`bitwise_lshift(other: Any) → ColumnOperators

    inherited from the `ColumnOperators.bitwise_lshift()` method of `ColumnOperators`

    Produce a bitwise LSHIFT operation, typically via the `<<` operator.

    New in version 2.0.2.

    See also

    Bitwise Operators

  method `sqlalchemy.ext.associationproxy.AssociationProxyInstance.`bitwise_not() → ColumnOperators

    inherited from the `ColumnOperators.bitwise_not()` method of `ColumnOperators`

    Produce a bitwise NOT operation, typically via the `~` operator.

    New in version 2.0.2.

    See also

    Bitwise Operators

  method `sqlalchemy.ext.associationproxy.AssociationProxyInstance.`bitwise_or(other: Any) → ColumnOperators

    inherited from the `ColumnOperators.bitwise_or()` method of `ColumnOperators`

    Produce a bitwise OR operation, typically via the `|` operator.

    New in version 2.0.2.

    See also

    Bitwise Operators

  method `sqlalchemy.ext.associationproxy.AssociationProxyInstance.`bitwise_rshift(other: Any) → ColumnOperators

    inherited from the `ColumnOperators.bitwise_rshift()` method of `ColumnOperators`

    Produce a bitwise RSHIFT operation, typically via the `>>` operator.

    New in version 2.0.2.

    See also

    Bitwise Operators

  method `sqlalchemy.ext.associationproxy.AssociationProxyInstance.`bitwise_xor(other: Any) → ColumnOperators

    inherited from the `ColumnOperators.bitwise_xor()` method of `ColumnOperators`

    Produce a bitwise XOR operation, typically via the `^` operator, or `#` for PostgreSQL.

    New in version 2.0.2.

    See also

    Bitwise Operators

  method `sqlalchemy.ext.associationproxy.AssociationProxyInstance.`bool_op(opstring: str, precedence: int = 0, python_impl: Callable[[...], Any] | None = None) → Callable[[Any], Operators]

    inherited from the `Operators.bool_op()` method of `Operators`

    Return a custom boolean operator.

    This method is shorthand for calling `Operators.op()` and passing the `Operators.op.is_comparison` flag with True. A key advantage to using `Operators.bool_op()` is that when using column constructs, the “boolean” nature of the returned expression will be present for PEP 484 purposes.

    See also

    `Operators.op()`

  method `sqlalchemy.ext.associationproxy.AssociationProxyInstance.`collate(collation: str) → ColumnOperators

    inherited from the `ColumnOperators.collate()` method of `ColumnOperators`

    Produce a `collate()` clause against the parent object, given the collation string.

    See also

    `collate()`

  attribute `sqlalchemy.ext.associationproxy.AssociationProxyInstance.`collection_class: Type[Any] | None
  method `sqlalchemy.ext.associationproxy.AssociationProxyInstance.`concat(other: Any) → ColumnOperators

    inherited from the `ColumnOperators.concat()` method of `ColumnOperators`

    Implement the ‘concat’ operator.

    In a column context, produces the clause `a || b`, or uses the `concat()` operator on MySQL.

  method `sqlalchemy.ext.associationproxy.AssociationProxyInstance.`contains(other: Any, **kw: Any) → ColumnOperators

    inherited from the `ColumnOperators.contains()` method of `ColumnOperators`

    Implement the ‘contains’ operator.

    Produces a LIKE expression that tests against a match for the middle of a string value:

        column LIKE '%' || <other> || '%'

    E.g.:

        stmt = select(sometable).\
            where(sometable.c.column.contains("foobar"))

    Since the operator uses `LIKE`, wildcard characters `"%"` and `"_"` that are present inside the <other> expression will behave like wildcards as well. For literal string values, the `ColumnOperators.contains.autoescape` flag may be set to `True` to apply escaping to occurrences of these characters within the string value so that they match as themselves and not as wildcard characters. Alternatively, the `ColumnOperators.contains.escape` parameter will establish a given character as an escape character which can be of use when the target expression is not a literal string.

    Parameters:

      - other – expression to be compared. This is usually a plain string value, but can also be an arbitrary SQL expression. LIKE wildcard characters `%` and `_` are not escaped by default unless the `ColumnOperators.contains.autoescape` flag is set to True.

      - autoescape –

        boolean; when True, establishes an escape character within the LIKE expression, then applies it to all occurrences of `"%"`, `"_"` and the escape character itself within the comparison value, which is assumed to be a literal string and not a SQL expression.

        An expression such as:

            somecolumn.contains("foo%bar", autoescape=True)

        Will render as:

            somecolumn LIKE '%' || :param || '%' ESCAPE '/'

        With the value of `:param` as `"foo/%bar"`.

      - escape –

        a character which when given will render with the `ESCAPE` keyword to establish that character as the escape character. This character can then be placed preceding occurrences of `%` and `_` to allow them to act as themselves and not wildcard characters.

        An expression such as:

            somecolumn.contains("foo/%bar", escape="^")

        Will render as:

            somecolumn LIKE '%' || :param || '%' ESCAPE '^'

        The parameter may also be combined with `ColumnOperators.contains.autoescape`:

            somecolumn.contains("foo%bar^bat", escape="^", autoescape=True)

        Where above, the given literal parameter will be converted to `"foo^%bar^^bat"` before being passed to the database.

    See also

    `ColumnOperators.startswith()`

    `ColumnOperators.endswith()`

    `ColumnOperators.like()`

  method `sqlalchemy.ext.associationproxy.AssociationProxyInstance.`delete(obj: Any) → None
  method `sqlalchemy.ext.associationproxy.AssociationProxyInstance.`desc() → ColumnOperators

    inherited from the `ColumnOperators.desc()` method of `ColumnOperators`

    Produce a `desc()` clause against the parent object.

  method `sqlalchemy.ext.associationproxy.AssociationProxyInstance.`distinct() → ColumnOperators

    inherited from the `ColumnOperators.distinct()` method of `ColumnOperators`

    Produce a `distinct()` clause against the parent object.

  method `sqlalchemy.ext.associationproxy.AssociationProxyInstance.`endswith(other: Any, escape: str | None = None, autoescape: bool = False) → ColumnOperators

    inherited from the `ColumnOperators.endswith()` method of `ColumnOperators`

    Implement the ‘endswith’ operator.

    Produces a LIKE expression that tests against a match for the end of a string value:

        column LIKE '%' || <other>

    E.g.:

        stmt = select(sometable).\
            where(sometable.c.column.endswith("foobar"))

    Since the operator uses `LIKE`, wildcard characters `"%"` and `"_"` that are present inside the <other> expression will behave like wildcards as well. For literal string values, the `ColumnOperators.endswith.autoescape` flag may be set to `True` to apply escaping to occurrences of these characters within the string value so that they match as themselves and not as wildcard characters. Alternatively, the `ColumnOperators.endswith.escape` parameter will establish a given character as an escape character which can be of use when the target expression is not a literal string.

    Parameters:

      - other – expression to be compared. This is usually a plain string value, but can also be an arbitrary SQL expression. LIKE wildcard characters `%` and `_` are not escaped by default unless the `ColumnOperators.endswith.autoescape` flag is set to True.

      - autoescape –

        boolean; when True, establishes an escape character within the LIKE expression, then applies it to all occurrences of `"%"`, `"_"` and the escape character itself within the comparison value, which is assumed to be a literal string and not a SQL expression.

        An expression such as:

            somecolumn.endswith("foo%bar", autoescape=True)

        Will render as:

            somecolumn LIKE '%' || :param ESCAPE '/'

        With the value of `:param` as `"foo/%bar"`.

      - escape –

        a character which when given will render with the `ESCAPE` keyword to establish that character as the escape character. This character can then be placed preceding occurrences of `%` and `_` to allow them to act as themselves and not wildcard characters.

        An expression such as:

            somecolumn.endswith("foo/%bar", escape="^")

        Will render as:

            somecolumn LIKE '%' || :param ESCAPE '^'

        The parameter may also be combined with `ColumnOperators.endswith.autoescape`:

            somecolumn.endswith("foo%bar^bat", escape="^", autoescape=True)

        Where above, the given literal parameter will be converted to `"foo^%bar^^bat"` before being passed to the database.

    See also

    `ColumnOperators.startswith()`

    `ColumnOperators.contains()`

    `ColumnOperators.like()`

  classmethod `sqlalchemy.ext.associationproxy.AssociationProxyInstance.`for_proxy(parent: AssociationProxy[_T], owning_class: Type[Any], parent_instance: Any) → AssociationProxyInstance[_T]
  method `sqlalchemy.ext.associationproxy.AssociationProxyInstance.`get(obj: Any) → _T | None | AssociationProxyInstance[_T]
  method `sqlalchemy.ext.associationproxy.AssociationProxyInstance.`has(criterion: _ColumnExpressionArgument[bool] | None = None, **kwargs: Any) → ColumnElement[bool]

    Produce a proxied ‘has’ expression using EXISTS.

    This expression will be a composed product using the `Comparator.any()` and/or `Comparator.has()` operators of the underlying proxied attributes.

  method `sqlalchemy.ext.associationproxy.AssociationProxyInstance.`icontains(other: Any, **kw: Any) → ColumnOperators

    inherited from the `ColumnOperators.icontains()` method of `ColumnOperators`

    Implement the `icontains` operator, e.g. case insensitive version of `ColumnOperators.contains()`.

    Produces a LIKE expression that tests against an insensitive match for the middle of a string value:

        lower(column) LIKE '%' || lower(<other>) || '%'

    E.g.:

        stmt = select(sometable).\
            where(sometable.c.column.icontains("foobar"))

    Since the operator uses `LIKE`, wildcard characters `"%"` and `"_"` that are present inside the <other> expression will behave like wildcards as well. For literal string values, the `ColumnOperators.icontains.autoescape` flag may be set to `True` to apply escaping to occurrences of these characters within the string value so that they match as themselves and not as wildcard characters. Alternatively, the `ColumnOperators.icontains.escape` parameter will establish a given character as an escape character which can be of use when the target expression is not a literal string.

    Parameters:

      - other – expression to be compared. This is usually a plain string value, but can also be an arbitrary SQL expression. LIKE wildcard characters `%` and `_` are not escaped by default unless the `ColumnOperators.icontains.autoescape` flag is set to True.

      - autoescape –

        boolean; when True, establishes an escape character within the LIKE expression, then applies it to all occurrences of `"%"`, `"_"` and the escape character itself within the comparison value, which is assumed to be a literal string and not a SQL expression.

        An expression such as:

            somecolumn.icontains("foo%bar", autoescape=True)

        Will render as:

            lower(somecolumn) LIKE '%' || lower(:param) || '%' ESCAPE '/'

        With the value of `:param` as `"foo/%bar"`.

      - escape –

        a character which when given will render with the `ESCAPE` keyword to establish that character as the escape character. This character can then be placed preceding occurrences of `%` and `_` to allow them to act as themselves and not wildcard characters.

        An expression such as:

            somecolumn.icontains("foo/%bar", escape="^")

        Will render as:

            lower(somecolumn) LIKE '%' || lower(:param) || '%' ESCAPE '^'

        The parameter may also be combined with `ColumnOperators.contains.autoescape`:

            somecolumn.icontains("foo%bar^bat", escape="^", autoescape=True)

        Where above, the given literal parameter will be converted to `"foo^%bar^^bat"` before being passed to the database.

    See also

    `ColumnOperators.contains()`

  method `sqlalchemy.ext.associationproxy.AssociationProxyInstance.`iendswith(other: Any, escape: str | None = None, autoescape: bool = False) → ColumnOperators

    inherited from the `ColumnOperators.iendswith()` method of `ColumnOperators`

    Implement the `iendswith` operator, e.g. case insensitive version of `ColumnOperators.endswith()`.

    Produces a LIKE expression that tests against an insensitive match for the end of a string value:

        lower(column) LIKE '%' || lower(<other>)

    E.g.:

        stmt = select(sometable).\
            where(sometable.c.column.iendswith("foobar"))

    Since the operator uses `LIKE`, wildcard characters `"%"` and `"_"` that are present inside the <other> expression will behave like wildcards as well. For literal string values, the `ColumnOperators.iendswith.autoescape` flag may be set to `True` to apply escaping to occurrences of these characters within the string value so that they match as themselves and not as wildcard characters. Alternatively, the `ColumnOperators.iendswith.escape` parameter will establish a given character as an escape character which can be of use when the target expression is not a literal string.

    Parameters:

      - other – expression to be compared. This is usually a plain string value, but can also be an arbitrary SQL expression. LIKE wildcard characters `%` and `_` are not escaped by default unless the `ColumnOperators.iendswith.autoescape` flag is set to True.

      - autoescape –

        boolean; when True, establishes an escape character within the LIKE expression, then applies it to all occurrences of `"%"`, `"_"` and the escape character itself within the comparison value, which is assumed to be a literal string and not a SQL expression.

        An expression such as:

            somecolumn.iendswith("foo%bar", autoescape=True)

        Will render as:

            lower(somecolumn) LIKE '%' || lower(:param) ESCAPE '/'

        With the value of `:param` as `"foo/%bar"`.

      - escape –

        a character which when given will render with the `ESCAPE` keyword to establish that character as the escape character. This character can then be placed preceding occurrences of `%` and `_` to allow them to act as themselves and not wildcard characters.

        An expression such as:

            somecolumn.iendswith("foo/%bar", escape="^")

        Will render as:

            lower(somecolumn) LIKE '%' || lower(:param) ESCAPE '^'

        The parameter may also be combined with `ColumnOperators.iendswith.autoescape`:

            somecolumn.endswith("foo%bar^bat", escape="^", autoescape=True)

        Where above, the given literal parameter will be converted to `"foo^%bar^^bat"` before being passed to the database.

    See also

    `ColumnOperators.endswith()`

  method `sqlalchemy.ext.associationproxy.AssociationProxyInstance.`ilike(other: Any, escape: str | None = None) → ColumnOperators

    inherited from the `ColumnOperators.ilike()` method of `ColumnOperators`

    Implement the `ilike` operator, e.g. case insensitive LIKE.

    In a column context, produces an expression either of the form:

        lower(a) LIKE lower(other)

    Or on backends that support the ILIKE operator:

        a ILIKE other

    E.g.:

        stmt = select(sometable).\
            where(sometable.c.column.ilike("%foobar%"))

    Parameters:

      - other – expression to be compared

      - escape –

        optional escape character, renders the `ESCAPE` keyword, e.g.:

            somecolumn.ilike("foo/%bar", escape="/")

    See also

    `ColumnOperators.like()`

  method `sqlalchemy.ext.associationproxy.AssociationProxyInstance.`in_(other: Any) → ColumnOperators

    inherited from the `ColumnOperators.in_()` method of `ColumnOperators`

    Implement the `in` operator.

    In a column context, produces the clause `column IN <other>`.

    The given parameter `other` may be:

    - A list of literal values, e.g.:

          stmt.where(column.in_([1, 2, 3]))

      In this calling form, the list of items is converted to a set of bound parameters the same length as the list given:

          WHERE COL IN (?, ?, ?)

    - A list of tuples may be provided if the comparison is against a `tuple_()` containing multiple expressions:

          from sqlalchemy import tuple_
          stmt.where(tuple_(col1, col2).in_([(1, 10), (2, 20), (3, 30)]))

    - An empty list, e.g.:

          stmt.where(column.in_([]))

      In this calling form, the expression renders an “empty set” expression. These expressions are tailored to individual backends and are generally trying to get an empty SELECT statement as a subquery. Such as on SQLite, the expression is:

          WHERE col IN (SELECT 1 FROM (SELECT 1) WHERE 1!=1)

      Changed in version 1.4: empty IN expressions now use an execution-time generated SELECT subquery in all cases.

    - A bound parameter, e.g. `bindparam()`, may be used if it includes the `bindparam.expanding` flag:

          stmt.where(column.in_(bindparam('value', expanding=True)))

      In this calling form, the expression renders a special non-SQL placeholder expression that looks like:

          WHERE COL IN ([EXPANDING_value])

      This placeholder expression is intercepted at statement execution time to be converted into the variable number of bound parameter form illustrated earlier. If the statement were executed as:

          connection.execute(stmt, {"value": [1, 2, 3]})

      The database would be passed a bound parameter for each value:

          WHERE COL IN (?, ?, ?)

      New in version 1.2: added “expanding” bound parameters

      If an empty list is passed, a special “empty list” expression, which is specific to the database in use, is rendered. On SQLite this would be:

          WHERE COL IN (SELECT 1 FROM (SELECT 1) WHERE 1!=1)

      New in version 1.3: “expanding” bound parameters now support empty lists

    - a `select()` construct, which is usually a correlated scalar select:

          stmt.where(
              column.in_(
                  select(othertable.c.y).
                  where(table.c.x == othertable.c.x)
              )
          )

      In this calling form, `ColumnOperators.in_()` renders as given:

          WHERE COL IN (SELECT othertable.y
          FROM othertable WHERE othertable.x = table.x)

    Parameters:

      other – a list of literals, a `select()` construct, or a `bindparam()` construct that includes the `bindparam.expanding` flag set to True.

  attribute `sqlalchemy.ext.associationproxy.AssociationProxyInstance.`info
  method `sqlalchemy.ext.associationproxy.AssociationProxyInstance.`is_(other: Any) → ColumnOperators

    inherited from the `ColumnOperators.is_()` method of `ColumnOperators`

    Implement the `IS` operator.

    Normally, `IS` is generated automatically when comparing to a value of `None`, which resolves to `NULL`. However, explicit usage of `IS` may be desirable if comparing to boolean values on certain platforms.

    See also

    `ColumnOperators.is_not()`

  method `sqlalchemy.ext.associationproxy.AssociationProxyInstance.`is_distinct_from(other: Any) → ColumnOperators

    inherited from the `ColumnOperators.is_distinct_from()` method of `ColumnOperators`

    Implement the `IS DISTINCT FROM` operator.

    Renders “a IS DISTINCT FROM b” on most platforms; on some such as SQLite may render “a IS NOT b”.

  method `sqlalchemy.ext.associationproxy.AssociationProxyInstance.`is_not(other: Any) → ColumnOperators

    inherited from the `ColumnOperators.is_not()` method of `ColumnOperators`

    Implement the `IS NOT` operator.

    Normally, `IS NOT` is generated automatically when comparing to a value of `None`, which resolves to `NULL`. However, explicit usage of `IS NOT` may be desirable if comparing to boolean values on certain platforms.

    Changed in version 1.4: The `is_not()` operator is renamed from `isnot()` in previous releases. The previous name remains available for backwards compatibility.

    See also

    `ColumnOperators.is_()`

  method `sqlalchemy.ext.associationproxy.AssociationProxyInstance.`is_not_distinct_from(other: Any) → ColumnOperators

    inherited from the `ColumnOperators.is_not_distinct_from()` method of `ColumnOperators`

    Implement the `IS NOT DISTINCT FROM` operator.

    Renders “a IS NOT DISTINCT FROM b” on most platforms; on some such as SQLite may render “a IS b”.

    Changed in version 1.4: The `is_not_distinct_from()` operator is renamed from `isnot_distinct_from()` in previous releases. The previous name remains available for backwards compatibility.

  method `sqlalchemy.ext.associationproxy.AssociationProxyInstance.`isnot(other: Any) → ColumnOperators

    inherited from the `ColumnOperators.isnot()` method of `ColumnOperators`

    Implement the `IS NOT` operator.

    Normally, `IS NOT` is generated automatically when comparing to a value of `None`, which resolves to `NULL`. However, explicit usage of `IS NOT` may be desirable if comparing to boolean values on certain platforms.

    Changed in version 1.4: The `is_not()` operator is renamed from `isnot()` in previous releases. The previous name remains available for backwards compatibility.

    See also

    `ColumnOperators.is_()`

  method `sqlalchemy.ext.associationproxy.AssociationProxyInstance.`isnot_distinct_from(other: Any) → ColumnOperators

    inherited from the `ColumnOperators.isnot_distinct_from()` method of `ColumnOperators`

    Implement the `IS NOT DISTINCT FROM` operator.

    Renders “a IS NOT DISTINCT FROM b” on most platforms; on some such as SQLite may render “a IS b”.

    Changed in version 1.4: The `is_not_distinct_from()` operator is renamed from `isnot_distinct_from()` in previous releases. The previous name remains available for backwards compatibility.

  method `sqlalchemy.ext.associationproxy.AssociationProxyInstance.`istartswith(other: Any, escape: str | None = None, autoescape: bool = False) → ColumnOperators

    inherited from the `ColumnOperators.istartswith()` method of `ColumnOperators`

    Implement the `istartswith` operator, e.g. case insensitive version of `ColumnOperators.startswith()`.

    Produces a LIKE expression that tests against an insensitive match for the start of a string value:

        lower(column) LIKE lower(<other>) || '%'

    E.g.:

        stmt = select(sometable).\
            where(sometable.c.column.istartswith("foobar"))

    Since the operator uses `LIKE`, wildcard characters `"%"` and `"_"` that are present inside the <other> expression will behave like wildcards as well. For literal string values, the `ColumnOperators.istartswith.autoescape` flag may be set to `True` to apply escaping to occurrences of these characters within the string value so that they match as themselves and not as wildcard characters. Alternatively, the `ColumnOperators.istartswith.escape` parameter will establish a given character as an escape character which can be of use when the target expression is not a literal string.

    Parameters:

      - other – expression to be compared. This is usually a plain string value, but can also be an arbitrary SQL expression. LIKE wildcard characters `%` and `_` are not escaped by default unless the `ColumnOperators.istartswith.autoescape` flag is set to True.

      - autoescape –

        boolean; when True, establishes an escape character within the LIKE expression, then applies it to all occurrences of `"%"`, `"_"` and the escape character itself within the comparison value, which is assumed to be a literal string and not a SQL expression.

        An expression such as:

            somecolumn.istartswith("foo%bar", autoescape=True)

        Will render as:

            lower(somecolumn) LIKE lower(:param) || '%' ESCAPE '/'

        With the value of `:param` as `"foo/%bar"`.

      - escape –

        a character which when given will render with the `ESCAPE` keyword to establish that character as the escape character. This character can then be placed preceding occurrences of `%` and `_` to allow them to act as themselves and not wildcard characters.

        An expression such as:

            somecolumn.istartswith("foo/%bar", escape="^")

        Will render as:

            lower(somecolumn) LIKE lower(:param) || '%' ESCAPE '^'

        The parameter may also be combined with `ColumnOperators.istartswith.autoescape`:

            somecolumn.istartswith("foo%bar^bat", escape="^", autoescape=True)

        Where above, the given literal parameter will be converted to `"foo^%bar^^bat"` before being passed to the database.

    See also

    `ColumnOperators.startswith()`

  method `sqlalchemy.ext.associationproxy.AssociationProxyInstance.`like(other: Any, escape: str | None = None) → ColumnOperators

    inherited from the `ColumnOperators.like()` method of `ColumnOperators`

    Implement the `like` operator.

    In a column context, produces the expression:

        a LIKE other

    E.g.:

        stmt = select(sometable).\
            where(sometable.c.column.like("%foobar%"))

    Parameters:

      - other – expression to be compared

      - escape –

        optional escape character, renders the `ESCAPE` keyword, e.g.:

            somecolumn.like("foo/%bar", escape="/")

    See also

    `ColumnOperators.ilike()`

  attribute `sqlalchemy.ext.associationproxy.AssociationProxyInstance.`local_attr

    The ‘local’ class attribute referenced by this `AssociationProxyInstance`.

    See also

    `AssociationProxyInstance.attr`

    `AssociationProxyInstance.remote_attr`

  method `sqlalchemy.ext.associationproxy.AssociationProxyInstance.`match(other: Any, **kwargs: Any) → ColumnOperators

    inherited from the `ColumnOperators.match()` method of `ColumnOperators`

    Implements a database-specific ‘match’ operator.

    `ColumnOperators.match()` attempts to resolve to a MATCH-like function or operator provided by the backend. Examples include:

    - PostgreSQL - renders `x @@ plainto_tsquery(y)`

      > Changed in version 2.0: `plainto_tsquery()` is used instead of `to_tsquery()` for PostgreSQL now; for compatibility with other forms, see Full Text Search.

    - MySQL - renders `MATCH (x) AGAINST (y IN BOOLEAN MODE)`

      See also

      `match` - MySQL specific construct with additional features.

    - Oracle - renders `CONTAINS(x, y)`

    - other backends may provide special implementations.

    - Backends without any special implementation will emit the operator as “MATCH”. This is compatible with SQLite, for example.

  method `sqlalchemy.ext.associationproxy.AssociationProxyInstance.`not_ilike(other: Any, escape: str | None = None) → ColumnOperators

    inherited from the `ColumnOperators.not_ilike()` method of `ColumnOperators`

    implement the `NOT ILIKE` operator.

    This is equivalent to using negation with `ColumnOperators.ilike()`, i.e. `~x.ilike(y)`.

    Changed in version 1.4: The `not_ilike()` operator is renamed from `notilike()` in previous releases. The previous name remains available for backwards compatibility.

    See also

    `ColumnOperators.ilike()`

  method `sqlalchemy.ext.associationproxy.AssociationProxyInstance.`not_in(other: Any) → ColumnOperators

    inherited from the `ColumnOperators.not_in()` method of `ColumnOperators`

    implement the `NOT IN` operator.

    This is equivalent to using negation with `ColumnOperators.in_()`, i.e. `~x.in_(y)`.

    In the case that `other` is an empty sequence, the compiler produces an “empty not in” expression. This defaults to the expression “1 = 1” to produce true in all cases. The `create_engine.empty_in_strategy` may be used to alter this behavior.

    Changed in version 1.4: The `not_in()` operator is renamed from `notin_()` in previous releases. The previous name remains available for backwards compatibility.

    Changed in version 1.2: The `ColumnOperators.in_()` and `ColumnOperators.not_in()` operators now produce a “static” expression for an empty IN sequence by default.

    See also

    `ColumnOperators.in_()`

  method `sqlalchemy.ext.associationproxy.AssociationProxyInstance.`not_like(other: Any, escape: str | None = None) → ColumnOperators

    inherited from the `ColumnOperators.not_like()` method of `ColumnOperators`

    implement the `NOT LIKE` operator.

    This is equivalent to using negation with `ColumnOperators.like()`, i.e. `~x.like(y)`.

    Changed in version 1.4: The `not_like()` operator is renamed from `notlike()` in previous releases. The previous name remains available for backwards compatibility.

    See also

    `ColumnOperators.like()`

  method `sqlalchemy.ext.associationproxy.AssociationProxyInstance.`notilike(other: Any, escape: str | None = None) → ColumnOperators

    inherited from the `ColumnOperators.notilike()` method of `ColumnOperators`

    implement the `NOT ILIKE` operator.

    This is equivalent to using negation with `ColumnOperators.ilike()`, i.e. `~x.ilike(y)`.

    Changed in version 1.4: The `not_ilike()` operator is renamed from `notilike()` in previous releases. The previous name remains available for backwards compatibility.

    See also

    `ColumnOperators.ilike()`

  method `sqlalchemy.ext.associationproxy.AssociationProxyInstance.`notin_(other: Any) → ColumnOperators

    inherited from the `ColumnOperators.notin_()` method of `ColumnOperators`

    implement the `NOT IN` operator.

    This is equivalent to using negation with `ColumnOperators.in_()`, i.e. `~x.in_(y)`.

    In the case that `other` is an empty sequence, the compiler produces an “empty not in” expression. This defaults to the expression “1 = 1” to produce true in all cases. The `create_engine.empty_in_strategy` may be used to alter this behavior.

    Changed in version 1.4: The `not_in()` operator is renamed from `notin_()` in previous releases. The previous name remains available for backwards compatibility.

    Changed in version 1.2: The `ColumnOperators.in_()` and `ColumnOperators.not_in()` operators now produce a “static” expression for an empty IN sequence by default.

    See also

    `ColumnOperators.in_()`

  method `sqlalchemy.ext.associationproxy.AssociationProxyInstance.`notlike(other: Any, escape: str | None = None) → ColumnOperators

    inherited from the `ColumnOperators.notlike()` method of `ColumnOperators`

    implement the `NOT LIKE` operator.

    This is equivalent to using negation with `ColumnOperators.like()`, i.e. `~x.like(y)`.

    Changed in version 1.4: The `not_like()` operator is renamed from `notlike()` in previous releases. The previous name remains available for backwards compatibility.

    See also

    `ColumnOperators.like()`

  method `sqlalchemy.ext.associationproxy.AssociationProxyInstance.`nulls_first() → ColumnOperators

    inherited from the `ColumnOperators.nulls_first()` method of `ColumnOperators`

    Produce a `nulls_first()` clause against the parent object.

    Changed in version 1.4: The `nulls_first()` operator is renamed from `nullsfirst()` in previous releases. The previous name remains available for backwards compatibility.

  method `sqlalchemy.ext.associationproxy.AssociationProxyInstance.`nulls_last() → ColumnOperators

    inherited from the `ColumnOperators.nulls_last()` method of `ColumnOperators`

    Produce a `nulls_last()` clause against the parent object.

    Changed in version 1.4: The `nulls_last()` operator is renamed from `nullslast()` in previous releases. The previous name remains available for backwards compatibility.

  method `sqlalchemy.ext.associationproxy.AssociationProxyInstance.`nullsfirst() → ColumnOperators

    inherited from the `ColumnOperators.nullsfirst()` method of `ColumnOperators`

    Produce a `nulls_first()` clause against the parent object.

    Changed in version 1.4: The `nulls_first()` operator is renamed from `nullsfirst()` in previous releases. The previous name remains available for backwards compatibility.

  method `sqlalchemy.ext.associationproxy.AssociationProxyInstance.`nullslast() → ColumnOperators

    inherited from the `ColumnOperators.nullslast()` method of `ColumnOperators`

    Produce a `nulls_last()` clause against the parent object.

    Changed in version 1.4: The `nulls_last()` operator is renamed from `nullslast()` in previous releases. The previous name remains available for backwards compatibility.

  method `sqlalchemy.ext.associationproxy.AssociationProxyInstance.`op(opstring: str, precedence: int = 0, is_comparison: bool = False, return_type: Type[TypeEngine[Any]] | TypeEngine[Any] | None = None, python_impl: Callable[..., Any] | None = None) → Callable[[Any], Operators]

    inherited from the `Operators.op()` method of `Operators`

    Produce a generic operator function.

    e.g.:

        somecolumn.op("*")(5)

    produces:

        somecolumn * 5

    This function can also be used to make bitwise operators explicit. For example:

        somecolumn.op('&')(0xff)

    is a bitwise AND of the value in `somecolumn`.

    Parameters:

      - opstring – a string which will be output as the infix operator between this element and the expression passed to the generated function.

      - precedence –

        precedence which the database is expected to apply to the operator in SQL expressions. This integer value acts as a hint for the SQL compiler to know when explicit parenthesis should be rendered around a particular operation. A lower number will cause the expression to be parenthesized when applied against another operator with higher precedence. The default value of `0` is lower than all operators except for the comma (`,`) and `AS` operators. A value of 100 will be higher or equal to all operators, and -100 will be lower than or equal to all operators.

        See also

        I’m using op() to generate a custom operator and my parenthesis are not coming out correctly - detailed description of how the SQLAlchemy SQL compiler renders parenthesis

      - is_comparison –

        legacy; if True, the operator will be considered as a “comparison” operator, that is which evaluates to a boolean true/false value, like `==`, `>`, etc. This flag is provided so that ORM relationships can establish that the operator is a comparison operator when used in a custom join condition.

        Using the `is_comparison` parameter is superseded by using the `Operators.bool_op()` method instead; this more succinct operator sets this parameter automatically, but also provides correct PEP 484 typing support as the returned object will express a “boolean” datatype, i.e. `BinaryExpression[bool]`.

      - return_type – a `TypeEngine` class or object that will force the return type of an expression produced by this operator to be of that type. By default, operators that specify `Operators.op.is_comparison` will resolve to `Boolean`, and those that do not will be of the same type as the left-hand operand.

      - python_impl –

        an optional Python function that can evaluate two Python values in the same way as this operator works when run on the database server. Useful for in-Python SQL expression evaluation functions, such as for ORM hybrid attributes, and the ORM “evaluator” used to match objects in a session after a multi-row update or delete.

        e.g.:

            >>> expr = column('x').op('+', python_impl=lambda a, b: a + b)('y')

        The operator for the above expression will also work for non-SQL left and right objects:

            >>> expr.operator(5, 10)
            15

        New in version 2.0.

    See also

    `Operators.bool_op()`

    Redefining and Creating New Operators

    Using custom operators in join conditions

  method `sqlalchemy.ext.associationproxy.AssociationProxyInstance.`operate(op: OperatorType, *other: Any, **kwargs: Any) → Operators

    inherited from the `Operators.operate()` method of `Operators`

    Operate on an argument.

    This is the lowest level of operation, raises `NotImplementedError` by default.

    Overriding this on a subclass can allow common behavior to be applied to all operations. For example, overriding `ColumnOperators` to apply `func.lower()` to the left and right side:

        class MyComparator(ColumnOperators):
            def operate(self, op, other, **kwargs):
                return op(func.lower(self), func.lower(other), **kwargs)

    Parameters:

      - op – Operator callable.

      - *other – the ‘other’ side of the operation. Will be a single scalar for most operations.

      - **kwargs – modifiers. These may be passed by special operators such as `ColumnOperators.contains()`.

  attribute `sqlalchemy.ext.associationproxy.AssociationProxyInstance.`parent: _AssociationProxyProtocol[_T]
  method `sqlalchemy.ext.associationproxy.AssociationProxyInstance.`regexp_match(pattern: Any, flags: str | None = None) → ColumnOperators

    inherited from the `ColumnOperators.regexp_match()` method of `ColumnOperators`

    Implements a database-specific ‘regexp match’ operator.

    E.g.:

        stmt = select(table.c.some_column).where(
            table.c.some_column.regexp_match('^(b|c)')
        )

    `ColumnOperators.regexp_match()` attempts to resolve to a REGEXP-like function or operator provided by the backend, however the specific regular expression syntax and flags available are not backend agnostic.

    Examples include:

    - PostgreSQL - renders `x ~ y` or `x !~ y` when negated.

    - Oracle - renders `REGEXP_LIKE(x, y)`

    - SQLite - uses SQLite’s `REGEXP` placeholder operator and calls into the Python `re.match()` builtin.

    - other backends may provide special implementations.

    - Backends without any special implementation will emit the operator as “REGEXP” or “NOT REGEXP”. This is compatible with SQLite and MySQL, for example.

    Regular expression support is currently implemented for Oracle, PostgreSQL, MySQL and MariaDB. Partial support is available for SQLite. Support among third-party dialects may vary.

    Parameters:

      - pattern – The regular expression pattern string or column clause.

      - flags – Any regular expression string flags to apply, passed as plain Python string only. These flags are backend specific. Some backends, like PostgreSQL and MariaDB, may alternatively specify the flags as part of the pattern. When using the ignore case flag ‘i’ in PostgreSQL, the ignore case regexp match operator `~*` or `!~*` will be used.

    New in version 1.4.

    Changed in version 1.4.48,: 2.0.18 Note that due to an implementation error, the “flags” parameter previously accepted SQL expression objects such as column expressions in addition to plain Python strings. This implementation did not work correctly with caching and was removed; strings only should be passed for the “flags” parameter, as these flags are rendered as literal inline values within SQL expressions.

    See also

    `ColumnOperators.regexp_replace()`

  method `sqlalchemy.ext.associationproxy.AssociationProxyInstance.`regexp_replace(pattern: Any, replacement: Any, flags: str | None = None) → ColumnOperators

    inherited from the `ColumnOperators.regexp_replace()` method of `ColumnOperators`

    Implements a database-specific ‘regexp replace’ operator.

    E.g.:

        stmt = select(
            table.c.some_column.regexp_replace(
                'b(..)',
                'XY',
                flags='g'
            )
        )

    `ColumnOperators.regexp_replace()` attempts to resolve to a REGEXP_REPLACE-like function provided by the backend, that usually emit the function `REGEXP_REPLACE()`. However, the specific regular expression syntax and flags available are not backend agnostic.

    Regular expression replacement support is currently implemented for Oracle, PostgreSQL, MySQL 8 or greater and MariaDB. Support among third-party dialects may vary.

    Parameters:

      - pattern – The regular expression pattern string or column clause.

      - pattern – The replacement string or column clause.

      - flags – Any regular expression string flags to apply, passed as plain Python string only. These flags are backend specific. Some backends, like PostgreSQL and MariaDB, may alternatively specify the flags as part of the pattern.

    New in version 1.4.

    Changed in version 1.4.48,: 2.0.18 Note that due to an implementation error, the “flags” parameter previously accepted SQL expression objects such as column expressions in addition to plain Python strings. This implementation did not work correctly with caching and was removed; strings only should be passed for the “flags” parameter, as these flags are rendered as literal inline values within SQL expressions.

    See also

    `ColumnOperators.regexp_match()`

  attribute `sqlalchemy.ext.associationproxy.AssociationProxyInstance.`remote_attr

    The ‘remote’ class attribute referenced by this `AssociationProxyInstance`.

    See also

    `AssociationProxyInstance.attr`

    `AssociationProxyInstance.local_attr`

  method `sqlalchemy.ext.associationproxy.AssociationProxyInstance.`reverse_operate(op: OperatorType, other: Any, **kwargs: Any) → Operators

    inherited from the `Operators.reverse_operate()` method of `Operators`

    Reverse operate on an argument.

    Usage is the same as `operate()`.

  attribute `sqlalchemy.ext.associationproxy.AssociationProxyInstance.`scalar

    Return `True` if this `AssociationProxyInstance` proxies a scalar relationship on the local side.

  method `sqlalchemy.ext.associationproxy.AssociationProxyInstance.`set(obj: Any, values: _T) → None
  method `sqlalchemy.ext.associationproxy.AssociationProxyInstance.`startswith(other: Any, escape: str | None = None, autoescape: bool = False) → ColumnOperators

    inherited from the `ColumnOperators.startswith()` method of `ColumnOperators`

    Implement the `startswith` operator.

    Produces a LIKE expression that tests against a match for the start of a string value:

        column LIKE <other> || '%'

    E.g.:

        stmt = select(sometable).\
            where(sometable.c.column.startswith("foobar"))

    Since the operator uses `LIKE`, wildcard characters `"%"` and `"_"` that are present inside the <other> expression will behave like wildcards as well. For literal string values, the `ColumnOperators.startswith.autoescape` flag may be set to `True` to apply escaping to occurrences of these characters within the string value so that they match as themselves and not as wildcard characters. Alternatively, the `ColumnOperators.startswith.escape` parameter will establish a given character as an escape character which can be of use when the target expression is not a literal string.

    Parameters:

      - other – expression to be compared. This is usually a plain string value, but can also be an arbitrary SQL expression. LIKE wildcard characters `%` and `_` are not escaped by default unless the `ColumnOperators.startswith.autoescape` flag is set to True.

      - autoescape –

        boolean; when True, establishes an escape character within the LIKE expression, then applies it to all occurrences of `"%"`, `"_"` and the escape character itself within the comparison value, which is assumed to be a literal string and not a SQL expression.

        An expression such as:

            somecolumn.startswith("foo%bar", autoescape=True)

        Will render as:

            somecolumn LIKE :param || '%' ESCAPE '/'

        With the value of `:param` as `"foo/%bar"`.

      - escape –

        a character which when given will render with the `ESCAPE` keyword to establish that character as the escape character. This character can then be placed preceding occurrences of `%` and `_` to allow them to act as themselves and not wildcard characters.

        An expression such as:

            somecolumn.startswith("foo/%bar", escape="^")

        Will render as:

            somecolumn LIKE :param || '%' ESCAPE '^'

        The parameter may also be combined with `ColumnOperators.startswith.autoescape`:

            somecolumn.startswith("foo%bar^bat", escape="^", autoescape=True)

        Where above, the given literal parameter will be converted to `"foo^%bar^^bat"` before being passed to the database.

    See also

    `ColumnOperators.endswith()`

    `ColumnOperators.contains()`

    `ColumnOperators.like()`

  attribute `sqlalchemy.ext.associationproxy.AssociationProxyInstance.`target_class: Type[Any]

    The intermediary class handled by this `AssociationProxyInstance`.

    Intercepted append/set/assignment events will result in the generation of new instances of this class.

  attribute `sqlalchemy.ext.associationproxy.AssociationProxyInstance.`timetuple: Literal[None] = None

    inherited from the `ColumnOperators.timetuple` attribute of `ColumnOperators`

    Hack, allows datetime objects to be compared on the LHS.

class sqlalchemy.ext.associationproxy.ObjectAssociationProxyInstance

  an `AssociationProxyInstance` that has an object as a target.

  Members

  __le__(), __lt__(), all_(), any(), any_(), asc(), attr, between(), bitwise_and(), bitwise_lshift(), bitwise_not(), bitwise_or(), bitwise_rshift(), bitwise_xor(), bool_op(), collate(), concat(), contains(), desc(), distinct(), endswith(), has(), icontains(), iendswith(), ilike(), in_(), is_(), is_distinct_from(), is_not(), is_not_distinct_from(), isnot(), isnot_distinct_from(), istartswith(), like(), local_attr, match(), not_ilike(), not_in(), not_like(), notilike(), notin_(), notlike(), nulls_first(), nulls_last(), nullsfirst(), nullslast(), op(), operate(), regexp_match(), regexp_replace(), remote_attr, reverse_operate(), scalar, startswith(), target_class, timetuple

  Class signature

  class `sqlalchemy.ext.associationproxy.ObjectAssociationProxyInstance` (`sqlalchemy.ext.associationproxy.AssociationProxyInstance`)

  method `sqlalchemy.ext.associationproxy.ObjectAssociationProxyInstance.`__le__(other: Any) → ColumnOperators

    inherited from the `sqlalchemy.sql.expression.ColumnOperators.__le__` method of `ColumnOperators`

    Implement the `<=` operator.

    In a column context, produces the clause `a <= b`.

  method `sqlalchemy.ext.associationproxy.ObjectAssociationProxyInstance.`__lt__(other: Any) → ColumnOperators

    inherited from the `sqlalchemy.sql.expression.ColumnOperators.__lt__` method of `ColumnOperators`

    Implement the `<` operator.

    In a column context, produces the clause `a < b`.

  method `sqlalchemy.ext.associationproxy.ObjectAssociationProxyInstance.`all_() → ColumnOperators

    inherited from the `ColumnOperators.all_()` method of `ColumnOperators`

    Produce an `all_()` clause against the parent object.

    See the documentation for `all_()` for examples.

    Note

    be sure to not confuse the newer `ColumnOperators.all_()` method with the legacy version of this method, the `Comparator.all()` method that’s specific to `ARRAY`, which uses a different calling style.

  method `sqlalchemy.ext.associationproxy.ObjectAssociationProxyInstance.`any(criterion: _ColumnExpressionArgument[bool] | None = None, **kwargs: Any) → ColumnElement[bool]

    inherited from the `AssociationProxyInstance.any()` method of `AssociationProxyInstance`

    Produce a proxied ‘any’ expression using EXISTS.

    This expression will be a composed product using the `Comparator.any()` and/or `Comparator.has()` operators of the underlying proxied attributes.

  method `sqlalchemy.ext.associationproxy.ObjectAssociationProxyInstance.`any_() → ColumnOperators

    inherited from the `ColumnOperators.any_()` method of `ColumnOperators`

    Produce an `any_()` clause against the parent object.

    See the documentation for `any_()` for examples.

    Note

    be sure to not confuse the newer `ColumnOperators.any_()` method with the legacy version of this method, the `Comparator.any()` method that’s specific to `ARRAY`, which uses a different calling style.

  method `sqlalchemy.ext.associationproxy.ObjectAssociationProxyInstance.`asc() → ColumnOperators

    inherited from the `ColumnOperators.asc()` method of `ColumnOperators`

    Produce a `asc()` clause against the parent object.

  attribute `sqlalchemy.ext.associationproxy.ObjectAssociationProxyInstance.`attr

    inherited from the `AssociationProxyInstance.attr` attribute of `AssociationProxyInstance`

    Return a tuple of `(local_attr, remote_attr)`.

    This attribute was originally intended to facilitate using the `Query.join()` method to join across the two relationships at once, however this makes use of a deprecated calling style.

    To use `select.join()` or `Query.join()` with an association proxy, the current method is to make use of the `AssociationProxyInstance.local_attr` and `AssociationProxyInstance.remote_attr` attributes separately:

        stmt = (
            select(Parent).
            join(Parent.proxied.local_attr).
            join(Parent.proxied.remote_attr)
        )

    A future release may seek to provide a more succinct join pattern for association proxy attributes.

    See also

    `AssociationProxyInstance.local_attr`

    `AssociationProxyInstance.remote_attr`

  method `sqlalchemy.ext.associationproxy.ObjectAssociationProxyInstance.`between(cleft: Any, cright: Any, symmetric: bool = False) → ColumnOperators

    inherited from the `ColumnOperators.between()` method of `ColumnOperators`

    Produce a `between()` clause against the parent object, given the lower and upper range.

  method `sqlalchemy.ext.associationproxy.ObjectAssociationProxyInstance.`bitwise_and(other: Any) → ColumnOperators

    inherited from the `ColumnOperators.bitwise_and()` method of `ColumnOperators`

    Produce a bitwise AND operation, typically via the `&` operator.

    New in version 2.0.2.

    See also

    Bitwise Operators

  method `sqlalchemy.ext.associationproxy.ObjectAssociationProxyInstance.`bitwise_lshift(other: Any) → ColumnOperators

    inherited from the `ColumnOperators.bitwise_lshift()` method of `ColumnOperators`

    Produce a bitwise LSHIFT operation, typically via the `<<` operator.

    New in version 2.0.2.

    See also

    Bitwise Operators

  method `sqlalchemy.ext.associationproxy.ObjectAssociationProxyInstance.`bitwise_not() → ColumnOperators

    inherited from the `ColumnOperators.bitwise_not()` method of `ColumnOperators`

    Produce a bitwise NOT operation, typically via the `~` operator.

    New in version 2.0.2.

    See also

    Bitwise Operators

  method `sqlalchemy.ext.associationproxy.ObjectAssociationProxyInstance.`bitwise_or(other: Any) → ColumnOperators

    inherited from the `ColumnOperators.bitwise_or()` method of `ColumnOperators`

    Produce a bitwise OR operation, typically via the `|` operator.

    New in version 2.0.2.

    See also

    Bitwise Operators

  method `sqlalchemy.ext.associationproxy.ObjectAssociationProxyInstance.`bitwise_rshift(other: Any) → ColumnOperators

    inherited from the `ColumnOperators.bitwise_rshift()` method of `ColumnOperators`

    Produce a bitwise RSHIFT operation, typically via the `>>` operator.

    New in version 2.0.2.

    See also

    Bitwise Operators

  method `sqlalchemy.ext.associationproxy.ObjectAssociationProxyInstance.`bitwise_xor(other: Any) → ColumnOperators

    inherited from the `ColumnOperators.bitwise_xor()` method of `ColumnOperators`

    Produce a bitwise XOR operation, typically via the `^` operator, or `#` for PostgreSQL.

    New in version 2.0.2.

    See also

    Bitwise Operators

  method `sqlalchemy.ext.associationproxy.ObjectAssociationProxyInstance.`bool_op(opstring: str, precedence: int = 0, python_impl: Callable[[...], Any] | None = None) → Callable[[Any], Operators]

    inherited from the `Operators.bool_op()` method of `Operators`

    Return a custom boolean operator.

    This method is shorthand for calling `Operators.op()` and passing the `Operators.op.is_comparison` flag with True. A key advantage to using `Operators.bool_op()` is that when using column constructs, the “boolean” nature of the returned expression will be present for PEP 484 purposes.

    See also

    `Operators.op()`

  method `sqlalchemy.ext.associationproxy.ObjectAssociationProxyInstance.`collate(collation: str) → ColumnOperators

    inherited from the `ColumnOperators.collate()` method of `ColumnOperators`

    Produce a `collate()` clause against the parent object, given the collation string.

    See also

    `collate()`

  method `sqlalchemy.ext.associationproxy.ObjectAssociationProxyInstance.`concat(other: Any) → ColumnOperators

    inherited from the `ColumnOperators.concat()` method of `ColumnOperators`

    Implement the ‘concat’ operator.

    In a column context, produces the clause `a || b`, or uses the `concat()` operator on MySQL.

  method `sqlalchemy.ext.associationproxy.ObjectAssociationProxyInstance.`contains(other: Any, **kw: Any) → ColumnElement[bool]

    Produce a proxied ‘contains’ expression using EXISTS.

    This expression will be a composed product using the `Comparator.any()`, `Comparator.has()`, and/or `Comparator.contains()` operators of the underlying proxied attributes.

  method `sqlalchemy.ext.associationproxy.ObjectAssociationProxyInstance.`desc() → ColumnOperators

    inherited from the `ColumnOperators.desc()` method of `ColumnOperators`

    Produce a `desc()` clause against the parent object.

  method `sqlalchemy.ext.associationproxy.ObjectAssociationProxyInstance.`distinct() → ColumnOperators

    inherited from the `ColumnOperators.distinct()` method of `ColumnOperators`

    Produce a `distinct()` clause against the parent object.

  method `sqlalchemy.ext.associationproxy.ObjectAssociationProxyInstance.`endswith(other: Any, escape: str | None = None, autoescape: bool = False) → ColumnOperators

    inherited from the `ColumnOperators.endswith()` method of `ColumnOperators`

    Implement the ‘endswith’ operator.

    Produces a LIKE expression that tests against a match for the end of a string value:

        column LIKE '%' || <other>

    E.g.:

        stmt = select(sometable).\
            where(sometable.c.column.endswith("foobar"))

    Since the operator uses `LIKE`, wildcard characters `"%"` and `"_"` that are present inside the <other> expression will behave like wildcards as well. For literal string values, the `ColumnOperators.endswith.autoescape` flag may be set to `True` to apply escaping to occurrences of these characters within the string value so that they match as themselves and not as wildcard characters. Alternatively, the `ColumnOperators.endswith.escape` parameter will establish a given character as an escape character which can be of use when the target expression is not a literal string.

    Parameters:

      - other – expression to be compared. This is usually a plain string value, but can also be an arbitrary SQL expression. LIKE wildcard characters `%` and `_` are not escaped by default unless the `ColumnOperators.endswith.autoescape` flag is set to True.

      - autoescape –

        boolean; when True, establishes an escape character within the LIKE expression, then applies it to all occurrences of `"%"`, `"_"` and the escape character itself within the comparison value, which is assumed to be a literal string and not a SQL expression.

        An expression such as:

            somecolumn.endswith("foo%bar", autoescape=True)

        Will render as:

            somecolumn LIKE '%' || :param ESCAPE '/'

        With the value of `:param` as `"foo/%bar"`.

      - escape –

        a character which when given will render with the `ESCAPE` keyword to establish that character as the escape character. This character can then be placed preceding occurrences of `%` and `_` to allow them to act as themselves and not wildcard characters.

        An expression such as:

            somecolumn.endswith("foo/%bar", escape="^")

        Will render as:

            somecolumn LIKE '%' || :param ESCAPE '^'

        The parameter may also be combined with `ColumnOperators.endswith.autoescape`:

            somecolumn.endswith("foo%bar^bat", escape="^", autoescape=True)

        Where above, the given literal parameter will be converted to `"foo^%bar^^bat"` before being passed to the database.

    See also

    `ColumnOperators.startswith()`

    `ColumnOperators.contains()`

    `ColumnOperators.like()`

  method `sqlalchemy.ext.associationproxy.ObjectAssociationProxyInstance.`has(criterion: _ColumnExpressionArgument[bool] | None = None, **kwargs: Any) → ColumnElement[bool]

    inherited from the `AssociationProxyInstance.has()` method of `AssociationProxyInstance`

    Produce a proxied ‘has’ expression using EXISTS.

    This expression will be a composed product using the `Comparator.any()` and/or `Comparator.has()` operators of the underlying proxied attributes.

  method `sqlalchemy.ext.associationproxy.ObjectAssociationProxyInstance.`icontains(other: Any, **kw: Any) → ColumnOperators

    inherited from the `ColumnOperators.icontains()` method of `ColumnOperators`

    Implement the `icontains` operator, e.g. case insensitive version of `ColumnOperators.contains()`.

    Produces a LIKE expression that tests against an insensitive match for the middle of a string value:

        lower(column) LIKE '%' || lower(<other>) || '%'

    E.g.:

        stmt = select(sometable).\
            where(sometable.c.column.icontains("foobar"))

    Since the operator uses `LIKE`, wildcard characters `"%"` and `"_"` that are present inside the <other> expression will behave like wildcards as well. For literal string values, the `ColumnOperators.icontains.autoescape` flag may be set to `True` to apply escaping to occurrences of these characters within the string value so that they match as themselves and not as wildcard characters. Alternatively, the `ColumnOperators.icontains.escape` parameter will establish a given character as an escape character which can be of use when the target expression is not a literal string.

    Parameters:

      - other – expression to be compared. This is usually a plain string value, but can also be an arbitrary SQL expression. LIKE wildcard characters `%` and `_` are not escaped by default unless the `ColumnOperators.icontains.autoescape` flag is set to True.

      - autoescape –

        boolean; when True, establishes an escape character within the LIKE expression, then applies it to all occurrences of `"%"`, `"_"` and the escape character itself within the comparison value, which is assumed to be a literal string and not a SQL expression.

        An expression such as:

            somecolumn.icontains("foo%bar", autoescape=True)

        Will render as:

            lower(somecolumn) LIKE '%' || lower(:param) || '%' ESCAPE '/'

        With the value of `:param` as `"foo/%bar"`.

      - escape –

        a character which when given will render with the `ESCAPE` keyword to establish that character as the escape character. This character can then be placed preceding occurrences of `%` and `_` to allow them to act as themselves and not wildcard characters.

        An expression such as:

            somecolumn.icontains("foo/%bar", escape="^")

        Will render as:

            lower(somecolumn) LIKE '%' || lower(:param) || '%' ESCAPE '^'

        The parameter may also be combined with `ColumnOperators.contains.autoescape`:

            somecolumn.icontains("foo%bar^bat", escape="^", autoescape=True)

        Where above, the given literal parameter will be converted to `"foo^%bar^^bat"` before being passed to the database.

    See also

    `ColumnOperators.contains()`

  method `sqlalchemy.ext.associationproxy.ObjectAssociationProxyInstance.`iendswith(other: Any, escape: str | None = None, autoescape: bool = False) → ColumnOperators

    inherited from the `ColumnOperators.iendswith()` method of `ColumnOperators`

    Implement the `iendswith` operator, e.g. case insensitive version of `ColumnOperators.endswith()`.

    Produces a LIKE expression that tests against an insensitive match for the end of a string value:

        lower(column) LIKE '%' || lower(<other>)

    E.g.:

        stmt = select(sometable).\
            where(sometable.c.column.iendswith("foobar"))

    Since the operator uses `LIKE`, wildcard characters `"%"` and `"_"` that are present inside the <other> expression will behave like wildcards as well. For literal string values, the `ColumnOperators.iendswith.autoescape` flag may be set to `True` to apply escaping to occurrences of these characters within the string value so that they match as themselves and not as wildcard characters. Alternatively, the `ColumnOperators.iendswith.escape` parameter will establish a given character as an escape character which can be of use when the target expression is not a literal string.

    Parameters:

      - other – expression to be compared. This is usually a plain string value, but can also be an arbitrary SQL expression. LIKE wildcard characters `%` and `_` are not escaped by default unless the `ColumnOperators.iendswith.autoescape` flag is set to True.

      - autoescape –

        boolean; when True, establishes an escape character within the LIKE expression, then applies it to all occurrences of `"%"`, `"_"` and the escape character itself within the comparison value, which is assumed to be a literal string and not a SQL expression.

        An expression such as:

            somecolumn.iendswith("foo%bar", autoescape=True)

        Will render as:

            lower(somecolumn) LIKE '%' || lower(:param) ESCAPE '/'

        With the value of `:param` as `"foo/%bar"`.

      - escape –

        a character which when given will render with the `ESCAPE` keyword to establish that character as the escape character. This character can then be placed preceding occurrences of `%` and `_` to allow them to act as themselves and not wildcard characters.

        An expression such as:

            somecolumn.iendswith("foo/%bar", escape="^")

        Will render as:

            lower(somecolumn) LIKE '%' || lower(:param) ESCAPE '^'

        The parameter may also be combined with `ColumnOperators.iendswith.autoescape`:

            somecolumn.endswith("foo%bar^bat", escape="^", autoescape=True)

        Where above, the given literal parameter will be converted to `"foo^%bar^^bat"` before being passed to the database.

    See also

    `ColumnOperators.endswith()`

  method `sqlalchemy.ext.associationproxy.ObjectAssociationProxyInstance.`ilike(other: Any, escape: str | None = None) → ColumnOperators

    inherited from the `ColumnOperators.ilike()` method of `ColumnOperators`

    Implement the `ilike` operator, e.g. case insensitive LIKE.

    In a column context, produces an expression either of the form:

        lower(a) LIKE lower(other)

    Or on backends that support the ILIKE operator:

        a ILIKE other

    E.g.:

        stmt = select(sometable).\
            where(sometable.c.column.ilike("%foobar%"))

    Parameters:

      - other – expression to be compared

      - escape –

        optional escape character, renders the `ESCAPE` keyword, e.g.:

            somecolumn.ilike("foo/%bar", escape="/")

    See also

    `ColumnOperators.like()`

  method `sqlalchemy.ext.associationproxy.ObjectAssociationProxyInstance.`in_(other: Any) → ColumnOperators

    inherited from the `ColumnOperators.in_()` method of `ColumnOperators`

    Implement the `in` operator.

    In a column context, produces the clause `column IN <other>`.

    The given parameter `other` may be:

    - A list of literal values, e.g.:

          stmt.where(column.in_([1, 2, 3]))

      In this calling form, the list of items is converted to a set of bound parameters the same length as the list given:

          WHERE COL IN (?, ?, ?)

    - A list of tuples may be provided if the comparison is against a `tuple_()` containing multiple expressions:

          from sqlalchemy import tuple_
          stmt.where(tuple_(col1, col2).in_([(1, 10), (2, 20), (3, 30)]))

    - An empty list, e.g.:

          stmt.where(column.in_([]))

      In this calling form, the expression renders an “empty set” expression. These expressions are tailored to individual backends and are generally trying to get an empty SELECT statement as a subquery. Such as on SQLite, the expression is:

          WHERE col IN (SELECT 1 FROM (SELECT 1) WHERE 1!=1)

      Changed in version 1.4: empty IN expressions now use an execution-time generated SELECT subquery in all cases.

    - A bound parameter, e.g. `bindparam()`, may be used if it includes the `bindparam.expanding` flag:

          stmt.where(column.in_(bindparam('value', expanding=True)))

      In this calling form, the expression renders a special non-SQL placeholder expression that looks like:

          WHERE COL IN ([EXPANDING_value])

      This placeholder expression is intercepted at statement execution time to be converted into the variable number of bound parameter form illustrated earlier. If the statement were executed as:

          connection.execute(stmt, {"value": [1, 2, 3]})

      The database would be passed a bound parameter for each value:

          WHERE COL IN (?, ?, ?)

      New in version 1.2: added “expanding” bound parameters

      If an empty list is passed, a special “empty list” expression, which is specific to the database in use, is rendered. On SQLite this would be:

          WHERE COL IN (SELECT 1 FROM (SELECT 1) WHERE 1!=1)

      New in version 1.3: “expanding” bound parameters now support empty lists

    - a `select()` construct, which is usually a correlated scalar select:

          stmt.where(
              column.in_(
                  select(othertable.c.y).
                  where(table.c.x == othertable.c.x)
              )
          )

      In this calling form, `ColumnOperators.in_()` renders as given:

          WHERE COL IN (SELECT othertable.y
          FROM othertable WHERE othertable.x = table.x)

    Parameters:

      other – a list of literals, a `select()` construct, or a `bindparam()` construct that includes the `bindparam.expanding` flag set to True.

  method `sqlalchemy.ext.associationproxy.ObjectAssociationProxyInstance.`is_(other: Any) → ColumnOperators

    inherited from the `ColumnOperators.is_()` method of `ColumnOperators`

    Implement the `IS` operator.

    Normally, `IS` is generated automatically when comparing to a value of `None`, which resolves to `NULL`. However, explicit usage of `IS` may be desirable if comparing to boolean values on certain platforms.

    See also

    `ColumnOperators.is_not()`

  method `sqlalchemy.ext.associationproxy.ObjectAssociationProxyInstance.`is_distinct_from(other: Any) → ColumnOperators

    inherited from the `ColumnOperators.is_distinct_from()` method of `ColumnOperators`

    Implement the `IS DISTINCT FROM` operator.

    Renders “a IS DISTINCT FROM b” on most platforms; on some such as SQLite may render “a IS NOT b”.

  method `sqlalchemy.ext.associationproxy.ObjectAssociationProxyInstance.`is_not(other: Any) → ColumnOperators

    inherited from the `ColumnOperators.is_not()` method of `ColumnOperators`

    Implement the `IS NOT` operator.

    Normally, `IS NOT` is generated automatically when comparing to a value of `None`, which resolves to `NULL`. However, explicit usage of `IS NOT` may be desirable if comparing to boolean values on certain platforms.

    Changed in version 1.4: The `is_not()` operator is renamed from `isnot()` in previous releases. The previous name remains available for backwards compatibility.

    See also

    `ColumnOperators.is_()`

  method `sqlalchemy.ext.associationproxy.ObjectAssociationProxyInstance.`is_not_distinct_from(other: Any) → ColumnOperators

    inherited from the `ColumnOperators.is_not_distinct_from()` method of `ColumnOperators`

    Implement the `IS NOT DISTINCT FROM` operator.

    Renders “a IS NOT DISTINCT FROM b” on most platforms; on some such as SQLite may render “a IS b”.

    Changed in version 1.4: The `is_not_distinct_from()` operator is renamed from `isnot_distinct_from()` in previous releases. The previous name remains available for backwards compatibility.

  method `sqlalchemy.ext.associationproxy.ObjectAssociationProxyInstance.`isnot(other: Any) → ColumnOperators

    inherited from the `ColumnOperators.isnot()` method of `ColumnOperators`

    Implement the `IS NOT` operator.

    Normally, `IS NOT` is generated automatically when comparing to a value of `None`, which resolves to `NULL`. However, explicit usage of `IS NOT` may be desirable if comparing to boolean values on certain platforms.

    Changed in version 1.4: The `is_not()` operator is renamed from `isnot()` in previous releases. The previous name remains available for backwards compatibility.

    See also

    `ColumnOperators.is_()`

  method `sqlalchemy.ext.associationproxy.ObjectAssociationProxyInstance.`isnot_distinct_from(other: Any) → ColumnOperators

    inherited from the `ColumnOperators.isnot_distinct_from()` method of `ColumnOperators`

    Implement the `IS NOT DISTINCT FROM` operator.

    Renders “a IS NOT DISTINCT FROM b” on most platforms; on some such as SQLite may render “a IS b”.

    Changed in version 1.4: The `is_not_distinct_from()` operator is renamed from `isnot_distinct_from()` in previous releases. The previous name remains available for backwards compatibility.

  method `sqlalchemy.ext.associationproxy.ObjectAssociationProxyInstance.`istartswith(other: Any, escape: str | None = None, autoescape: bool = False) → ColumnOperators

    inherited from the `ColumnOperators.istartswith()` method of `ColumnOperators`

    Implement the `istartswith` operator, e.g. case insensitive version of `ColumnOperators.startswith()`.

    Produces a LIKE expression that tests against an insensitive match for the start of a string value:

        lower(column) LIKE lower(<other>) || '%'

    E.g.:

        stmt = select(sometable).\
            where(sometable.c.column.istartswith("foobar"))

    Since the operator uses `LIKE`, wildcard characters `"%"` and `"_"` that are present inside the <other> expression will behave like wildcards as well. For literal string values, the `ColumnOperators.istartswith.autoescape` flag may be set to `True` to apply escaping to occurrences of these characters within the string value so that they match as themselves and not as wildcard characters. Alternatively, the `ColumnOperators.istartswith.escape` parameter will establish a given character as an escape character which can be of use when the target expression is not a literal string.

    Parameters:

      - other – expression to be compared. This is usually a plain string value, but can also be an arbitrary SQL expression. LIKE wildcard characters `%` and `_` are not escaped by default unless the `ColumnOperators.istartswith.autoescape` flag is set to True.

      - autoescape –

        boolean; when True, establishes an escape character within the LIKE expression, then applies it to all occurrences of `"%"`, `"_"` and the escape character itself within the comparison value, which is assumed to be a literal string and not a SQL expression.

        An expression such as:

            somecolumn.istartswith("foo%bar", autoescape=True)

        Will render as:

            lower(somecolumn) LIKE lower(:param) || '%' ESCAPE '/'

        With the value of `:param` as `"foo/%bar"`.

      - escape –

        a character which when given will render with the `ESCAPE` keyword to establish that character as the escape character. This character can then be placed preceding occurrences of `%` and `_` to allow them to act as themselves and not wildcard characters.

        An expression such as:

            somecolumn.istartswith("foo/%bar", escape="^")

        Will render as:

            lower(somecolumn) LIKE lower(:param) || '%' ESCAPE '^'

        The parameter may also be combined with `ColumnOperators.istartswith.autoescape`:

            somecolumn.istartswith("foo%bar^bat", escape="^", autoescape=True)

        Where above, the given literal parameter will be converted to `"foo^%bar^^bat"` before being passed to the database.

    See also

    `ColumnOperators.startswith()`

  method `sqlalchemy.ext.associationproxy.ObjectAssociationProxyInstance.`like(other: Any, escape: str | None = None) → ColumnOperators

    inherited from the `ColumnOperators.like()` method of `ColumnOperators`

    Implement the `like` operator.

    In a column context, produces the expression:

        a LIKE other

    E.g.:

        stmt = select(sometable).\
            where(sometable.c.column.like("%foobar%"))

    Parameters:

      - other – expression to be compared

      - escape –

        optional escape character, renders the `ESCAPE` keyword, e.g.:

            somecolumn.like("foo/%bar", escape="/")

    See also

    `ColumnOperators.ilike()`

  attribute `sqlalchemy.ext.associationproxy.ObjectAssociationProxyInstance.`local_attr

    inherited from the `AssociationProxyInstance.local_attr` attribute of `AssociationProxyInstance`

    The ‘local’ class attribute referenced by this `AssociationProxyInstance`.

    See also

    `AssociationProxyInstance.attr`

    `AssociationProxyInstance.remote_attr`

  method `sqlalchemy.ext.associationproxy.ObjectAssociationProxyInstance.`match(other: Any, **kwargs: Any) → ColumnOperators

    inherited from the `ColumnOperators.match()` method of `ColumnOperators`

    Implements a database-specific ‘match’ operator.

    `ColumnOperators.match()` attempts to resolve to a MATCH-like function or operator provided by the backend. Examples include:

    - PostgreSQL - renders `x @@ plainto_tsquery(y)`

      > Changed in version 2.0: `plainto_tsquery()` is used instead of `to_tsquery()` for PostgreSQL now; for compatibility with other forms, see Full Text Search.

    - MySQL - renders `MATCH (x) AGAINST (y IN BOOLEAN MODE)`

      See also

      `match` - MySQL specific construct with additional features.

    - Oracle - renders `CONTAINS(x, y)`

    - other backends may provide special implementations.

    - Backends without any special implementation will emit the operator as “MATCH”. This is compatible with SQLite, for example.

  method `sqlalchemy.ext.associationproxy.ObjectAssociationProxyInstance.`not_ilike(other: Any, escape: str | None = None) → ColumnOperators

    inherited from the `ColumnOperators.not_ilike()` method of `ColumnOperators`

    implement the `NOT ILIKE` operator.

    This is equivalent to using negation with `ColumnOperators.ilike()`, i.e. `~x.ilike(y)`.

    Changed in version 1.4: The `not_ilike()` operator is renamed from `notilike()` in previous releases. The previous name remains available for backwards compatibility.

    See also

    `ColumnOperators.ilike()`

  method `sqlalchemy.ext.associationproxy.ObjectAssociationProxyInstance.`not_in(other: Any) → ColumnOperators

    inherited from the `ColumnOperators.not_in()` method of `ColumnOperators`

    implement the `NOT IN` operator.

    This is equivalent to using negation with `ColumnOperators.in_()`, i.e. `~x.in_(y)`.

    In the case that `other` is an empty sequence, the compiler produces an “empty not in” expression. This defaults to the expression “1 = 1” to produce true in all cases. The `create_engine.empty_in_strategy` may be used to alter this behavior.

    Changed in version 1.4: The `not_in()` operator is renamed from `notin_()` in previous releases. The previous name remains available for backwards compatibility.

    Changed in version 1.2: The `ColumnOperators.in_()` and `ColumnOperators.not_in()` operators now produce a “static” expression for an empty IN sequence by default.

    See also

    `ColumnOperators.in_()`

  method `sqlalchemy.ext.associationproxy.ObjectAssociationProxyInstance.`not_like(other: Any, escape: str | None = None) → ColumnOperators

    inherited from the `ColumnOperators.not_like()` method of `ColumnOperators`

    implement the `NOT LIKE` operator.

    This is equivalent to using negation with `ColumnOperators.like()`, i.e. `~x.like(y)`.

    Changed in version 1.4: The `not_like()` operator is renamed from `notlike()` in previous releases. The previous name remains available for backwards compatibility.

    See also

    `ColumnOperators.like()`

  method `sqlalchemy.ext.associationproxy.ObjectAssociationProxyInstance.`notilike(other: Any, escape: str | None = None) → ColumnOperators

    inherited from the `ColumnOperators.notilike()` method of `ColumnOperators`

    implement the `NOT ILIKE` operator.

    This is equivalent to using negation with `ColumnOperators.ilike()`, i.e. `~x.ilike(y)`.

    Changed in version 1.4: The `not_ilike()` operator is renamed from `notilike()` in previous releases. The previous name remains available for backwards compatibility.

    See also

    `ColumnOperators.ilike()`

  method `sqlalchemy.ext.associationproxy.ObjectAssociationProxyInstance.`notin_(other: Any) → ColumnOperators

    inherited from the `ColumnOperators.notin_()` method of `ColumnOperators`

    implement the `NOT IN` operator.

    This is equivalent to using negation with `ColumnOperators.in_()`, i.e. `~x.in_(y)`.

    In the case that `other` is an empty sequence, the compiler produces an “empty not in” expression. This defaults to the expression “1 = 1” to produce true in all cases. The `create_engine.empty_in_strategy` may be used to alter this behavior.

    Changed in version 1.4: The `not_in()` operator is renamed from `notin_()` in previous releases. The previous name remains available for backwards compatibility.

    Changed in version 1.2: The `ColumnOperators.in_()` and `ColumnOperators.not_in()` operators now produce a “static” expression for an empty IN sequence by default.

    See also

    `ColumnOperators.in_()`

  method `sqlalchemy.ext.associationproxy.ObjectAssociationProxyInstance.`notlike(other: Any, escape: str | None = None) → ColumnOperators

    inherited from the `ColumnOperators.notlike()` method of `ColumnOperators`

    implement the `NOT LIKE` operator.

    This is equivalent to using negation with `ColumnOperators.like()`, i.e. `~x.like(y)`.

    Changed in version 1.4: The `not_like()` operator is renamed from `notlike()` in previous releases. The previous name remains available for backwards compatibility.

    See also

    `ColumnOperators.like()`

  method `sqlalchemy.ext.associationproxy.ObjectAssociationProxyInstance.`nulls_first() → ColumnOperators

    inherited from the `ColumnOperators.nulls_first()` method of `ColumnOperators`

    Produce a `nulls_first()` clause against the parent object.

    Changed in version 1.4: The `nulls_first()` operator is renamed from `nullsfirst()` in previous releases. The previous name remains available for backwards compatibility.

  method `sqlalchemy.ext.associationproxy.ObjectAssociationProxyInstance.`nulls_last() → ColumnOperators

    inherited from the `ColumnOperators.nulls_last()` method of `ColumnOperators`

    Produce a `nulls_last()` clause against the parent object.

    Changed in version 1.4: The `nulls_last()` operator is renamed from `nullslast()` in previous releases. The previous name remains available for backwards compatibility.

  method `sqlalchemy.ext.associationproxy.ObjectAssociationProxyInstance.`nullsfirst() → ColumnOperators

    inherited from the `ColumnOperators.nullsfirst()` method of `ColumnOperators`

    Produce a `nulls_first()` clause against the parent object.

    Changed in version 1.4: The `nulls_first()` operator is renamed from `nullsfirst()` in previous releases. The previous name remains available for backwards compatibility.

  method `sqlalchemy.ext.associationproxy.ObjectAssociationProxyInstance.`nullslast() → ColumnOperators

    inherited from the `ColumnOperators.nullslast()` method of `ColumnOperators`

    Produce a `nulls_last()` clause against the parent object.

    Changed in version 1.4: The `nulls_last()` operator is renamed from `nullslast()` in previous releases. The previous name remains available for backwards compatibility.

  method `sqlalchemy.ext.associationproxy.ObjectAssociationProxyInstance.`op(opstring: str, precedence: int = 0, is_comparison: bool = False, return_type: Type[TypeEngine[Any]] | TypeEngine[Any] | None = None, python_impl: Callable[..., Any] | None = None) → Callable[[Any], Operators]

    inherited from the `Operators.op()` method of `Operators`

    Produce a generic operator function.

    e.g.:

        somecolumn.op("*")(5)

    produces:

        somecolumn * 5

    This function can also be used to make bitwise operators explicit. For example:

        somecolumn.op('&')(0xff)

    is a bitwise AND of the value in `somecolumn`.

    Parameters:

      - opstring – a string which will be output as the infix operator between this element and the expression passed to the generated function.

      - precedence –

        precedence which the database is expected to apply to the operator in SQL expressions. This integer value acts as a hint for the SQL compiler to know when explicit parenthesis should be rendered around a particular operation. A lower number will cause the expression to be parenthesized when applied against another operator with higher precedence. The default value of `0` is lower than all operators except for the comma (`,`) and `AS` operators. A value of 100 will be higher or equal to all operators, and -100 will be lower than or equal to all operators.

        See also

        I’m using op() to generate a custom operator and my parenthesis are not coming out correctly - detailed description of how the SQLAlchemy SQL compiler renders parenthesis

      - is_comparison –

        legacy; if True, the operator will be considered as a “comparison” operator, that is which evaluates to a boolean true/false value, like `==`, `>`, etc. This flag is provided so that ORM relationships can establish that the operator is a comparison operator when used in a custom join condition.

        Using the `is_comparison` parameter is superseded by using the `Operators.bool_op()` method instead; this more succinct operator sets this parameter automatically, but also provides correct PEP 484 typing support as the returned object will express a “boolean” datatype, i.e. `BinaryExpression[bool]`.

      - return_type – a `TypeEngine` class or object that will force the return type of an expression produced by this operator to be of that type. By default, operators that specify `Operators.op.is_comparison` will resolve to `Boolean`, and those that do not will be of the same type as the left-hand operand.

      - python_impl –

        an optional Python function that can evaluate two Python values in the same way as this operator works when run on the database server. Useful for in-Python SQL expression evaluation functions, such as for ORM hybrid attributes, and the ORM “evaluator” used to match objects in a session after a multi-row update or delete.

        e.g.:

            >>> expr = column('x').op('+', python_impl=lambda a, b: a + b)('y')

        The operator for the above expression will also work for non-SQL left and right objects:

            >>> expr.operator(5, 10)
            15

        New in version 2.0.

    See also

    `Operators.bool_op()`

    Redefining and Creating New Operators

    Using custom operators in join conditions

  method `sqlalchemy.ext.associationproxy.ObjectAssociationProxyInstance.`operate(op: OperatorType, *other: Any, **kwargs: Any) → Operators

    inherited from the `Operators.operate()` method of `Operators`

    Operate on an argument.

    This is the lowest level of operation, raises `NotImplementedError` by default.

    Overriding this on a subclass can allow common behavior to be applied to all operations. For example, overriding `ColumnOperators` to apply `func.lower()` to the left and right side:

        class MyComparator(ColumnOperators):
            def operate(self, op, other, **kwargs):
                return op(func.lower(self), func.lower(other), **kwargs)

    Parameters:

      - op – Operator callable.

      - *other – the ‘other’ side of the operation. Will be a single scalar for most operations.

      - **kwargs – modifiers. These may be passed by special operators such as `ColumnOperators.contains()`.

  method `sqlalchemy.ext.associationproxy.ObjectAssociationProxyInstance.`regexp_match(pattern: Any, flags: str | None = None) → ColumnOperators

    inherited from the `ColumnOperators.regexp_match()` method of `ColumnOperators`

    Implements a database-specific ‘regexp match’ operator.

    E.g.:

        stmt = select(table.c.some_column).where(
            table.c.some_column.regexp_match('^(b|c)')
        )

    `ColumnOperators.regexp_match()` attempts to resolve to a REGEXP-like function or operator provided by the backend, however the specific regular expression syntax and flags available are not backend agnostic.

    Examples include:

    - PostgreSQL - renders `x ~ y` or `x !~ y` when negated.

    - Oracle - renders `REGEXP_LIKE(x, y)`

    - SQLite - uses SQLite’s `REGEXP` placeholder operator and calls into the Python `re.match()` builtin.

    - other backends may provide special implementations.

    - Backends without any special implementation will emit the operator as “REGEXP” or “NOT REGEXP”. This is compatible with SQLite and MySQL, for example.

    Regular expression support is currently implemented for Oracle, PostgreSQL, MySQL and MariaDB. Partial support is available for SQLite. Support among third-party dialects may vary.

    Parameters:

      - pattern – The regular expression pattern string or column clause.

      - flags – Any regular expression string flags to apply, passed as plain Python string only. These flags are backend specific. Some backends, like PostgreSQL and MariaDB, may alternatively specify the flags as part of the pattern. When using the ignore case flag ‘i’ in PostgreSQL, the ignore case regexp match operator `~*` or `!~*` will be used.

    New in version 1.4.

    Changed in version 1.4.48,: 2.0.18 Note that due to an implementation error, the “flags” parameter previously accepted SQL expression objects such as column expressions in addition to plain Python strings. This implementation did not work correctly with caching and was removed; strings only should be passed for the “flags” parameter, as these flags are rendered as literal inline values within SQL expressions.

    See also

    `ColumnOperators.regexp_replace()`

  method `sqlalchemy.ext.associationproxy.ObjectAssociationProxyInstance.`regexp_replace(pattern: Any, replacement: Any, flags: str | None = None) → ColumnOperators

    inherited from the `ColumnOperators.regexp_replace()` method of `ColumnOperators`

    Implements a database-specific ‘regexp replace’ operator.

    E.g.:

        stmt = select(
            table.c.some_column.regexp_replace(
                'b(..)',
                'XY',
                flags='g'
            )
        )

    `ColumnOperators.regexp_replace()` attempts to resolve to a REGEXP_REPLACE-like function provided by the backend, that usually emit the function `REGEXP_REPLACE()`. However, the specific regular expression syntax and flags available are not backend agnostic.

    Regular expression replacement support is currently implemented for Oracle, PostgreSQL, MySQL 8 or greater and MariaDB. Support among third-party dialects may vary.

    Parameters:

      - pattern – The regular expression pattern string or column clause.

      - pattern – The replacement string or column clause.

      - flags – Any regular expression string flags to apply, passed as plain Python string only. These flags are backend specific. Some backends, like PostgreSQL and MariaDB, may alternatively specify the flags as part of the pattern.

    New in version 1.4.

    Changed in version 1.4.48,: 2.0.18 Note that due to an implementation error, the “flags” parameter previously accepted SQL expression objects such as column expressions in addition to plain Python strings. This implementation did not work correctly with caching and was removed; strings only should be passed for the “flags” parameter, as these flags are rendered as literal inline values within SQL expressions.

    See also

    `ColumnOperators.regexp_match()`

  attribute `sqlalchemy.ext.associationproxy.ObjectAssociationProxyInstance.`remote_attr

    inherited from the `AssociationProxyInstance.remote_attr` attribute of `AssociationProxyInstance`

    The ‘remote’ class attribute referenced by this `AssociationProxyInstance`.

    See also

    `AssociationProxyInstance.attr`

    `AssociationProxyInstance.local_attr`

  method `sqlalchemy.ext.associationproxy.ObjectAssociationProxyInstance.`reverse_operate(op: OperatorType, other: Any, **kwargs: Any) → Operators

    inherited from the `Operators.reverse_operate()` method of `Operators`

    Reverse operate on an argument.

    Usage is the same as `operate()`.

  attribute `sqlalchemy.ext.associationproxy.ObjectAssociationProxyInstance.`scalar

    inherited from the `AssociationProxyInstance.scalar` attribute of `AssociationProxyInstance`

    Return `True` if this `AssociationProxyInstance` proxies a scalar relationship on the local side.

  method `sqlalchemy.ext.associationproxy.ObjectAssociationProxyInstance.`startswith(other: Any, escape: str | None = None, autoescape: bool = False) → ColumnOperators

    inherited from the `ColumnOperators.startswith()` method of `ColumnOperators`

    Implement the `startswith` operator.

    Produces a LIKE expression that tests against a match for the start of a string value:

        column LIKE <other> || '%'

    E.g.:

        stmt = select(sometable).\
            where(sometable.c.column.startswith("foobar"))

    Since the operator uses `LIKE`, wildcard characters `"%"` and `"_"` that are present inside the <other> expression will behave like wildcards as well. For literal string values, the `ColumnOperators.startswith.autoescape` flag may be set to `True` to apply escaping to occurrences of these characters within the string value so that they match as themselves and not as wildcard characters. Alternatively, the `ColumnOperators.startswith.escape` parameter will establish a given character as an escape character which can be of use when the target expression is not a literal string.

    Parameters:

      - other – expression to be compared. This is usually a plain string value, but can also be an arbitrary SQL expression. LIKE wildcard characters `%` and `_` are not escaped by default unless the `ColumnOperators.startswith.autoescape` flag is set to True.

      - autoescape –

        boolean; when True, establishes an escape character within the LIKE expression, then applies it to all occurrences of `"%"`, `"_"` and the escape character itself within the comparison value, which is assumed to be a literal string and not a SQL expression.

        An expression such as:

            somecolumn.startswith("foo%bar", autoescape=True)

        Will render as:

            somecolumn LIKE :param || '%' ESCAPE '/'

        With the value of `:param` as `"foo/%bar"`.

      - escape –

        a character which when given will render with the `ESCAPE` keyword to establish that character as the escape character. This character can then be placed preceding occurrences of `%` and `_` to allow them to act as themselves and not wildcard characters.

        An expression such as:

            somecolumn.startswith("foo/%bar", escape="^")

        Will render as:

            somecolumn LIKE :param || '%' ESCAPE '^'

        The parameter may also be combined with `ColumnOperators.startswith.autoescape`:

            somecolumn.startswith("foo%bar^bat", escape="^", autoescape=True)

        Where above, the given literal parameter will be converted to `"foo^%bar^^bat"` before being passed to the database.

    See also

    `ColumnOperators.endswith()`

    `ColumnOperators.contains()`

    `ColumnOperators.like()`

  attribute `sqlalchemy.ext.associationproxy.ObjectAssociationProxyInstance.`target_class: Type[Any]

    The intermediary class handled by this `AssociationProxyInstance`.

    Intercepted append/set/assignment events will result in the generation of new instances of this class.

  attribute `sqlalchemy.ext.associationproxy.ObjectAssociationProxyInstance.`timetuple: Literal[None] = None

    inherited from the `ColumnOperators.timetuple` attribute of `ColumnOperators`

    Hack, allows datetime objects to be compared on the LHS.

class sqlalchemy.ext.associationproxy.ColumnAssociationProxyInstance

  an `AssociationProxyInstance` that has a database column as a target.

  Members

  __le__(), __lt__(), __ne__(), all_(), any(), any_(), asc(), attr, between(), bitwise_and(), bitwise_lshift(), bitwise_not(), bitwise_or(), bitwise_rshift(), bitwise_xor(), bool_op(), collate(), concat(), contains(), desc(), distinct(), endswith(), has(), icontains(), iendswith(), ilike(), in_(), is_(), is_distinct_from(), is_not(), is_not_distinct_from(), isnot(), isnot_distinct_from(), istartswith(), like(), local_attr, match(), not_ilike(), not_in(), not_like(), notilike(), notin_(), notlike(), nulls_first(), nulls_last(), nullsfirst(), nullslast(), op(), operate(), regexp_match(), regexp_replace(), remote_attr, reverse_operate(), scalar, startswith(), target_class, timetuple

  Class signature

  class `sqlalchemy.ext.associationproxy.ColumnAssociationProxyInstance` (`sqlalchemy.ext.associationproxy.AssociationProxyInstance`)

  method `sqlalchemy.ext.associationproxy.ColumnAssociationProxyInstance.`__le__(other: Any) → ColumnOperators

    inherited from the `sqlalchemy.sql.expression.ColumnOperators.__le__` method of `ColumnOperators`

    Implement the `<=` operator.

    In a column context, produces the clause `a <= b`.

  method `sqlalchemy.ext.associationproxy.ColumnAssociationProxyInstance.`__lt__(other: Any) → ColumnOperators

    inherited from the `sqlalchemy.sql.expression.ColumnOperators.__lt__` method of `ColumnOperators`

    Implement the `<` operator.

    In a column context, produces the clause `a < b`.

  method `sqlalchemy.ext.associationproxy.ColumnAssociationProxyInstance.`__ne__(other: Any) → ColumnOperators

    inherited from the `sqlalchemy.sql.expression.ColumnOperators.__ne__` method of `ColumnOperators`

    Implement the `!=` operator.

    In a column context, produces the clause `a != b`. If the target is `None`, produces `a IS NOT NULL`.

  method `sqlalchemy.ext.associationproxy.ColumnAssociationProxyInstance.`all_() → ColumnOperators

    inherited from the `ColumnOperators.all_()` method of `ColumnOperators`

    Produce an `all_()` clause against the parent object.

    See the documentation for `all_()` for examples.

    Note

    be sure to not confuse the newer `ColumnOperators.all_()` method with the legacy version of this method, the `Comparator.all()` method that’s specific to `ARRAY`, which uses a different calling style.

  method `sqlalchemy.ext.associationproxy.ColumnAssociationProxyInstance.`any(criterion: _ColumnExpressionArgument[bool] | None = None, **kwargs: Any) → ColumnElement[bool]

    inherited from the `AssociationProxyInstance.any()` method of `AssociationProxyInstance`

    Produce a proxied ‘any’ expression using EXISTS.

    This expression will be a composed product using the `Comparator.any()` and/or `Comparator.has()` operators of the underlying proxied attributes.

  method `sqlalchemy.ext.associationproxy.ColumnAssociationProxyInstance.`any_() → ColumnOperators

    inherited from the `ColumnOperators.any_()` method of `ColumnOperators`

    Produce an `any_()` clause against the parent object.

    See the documentation for `any_()` for examples.

    Note

    be sure to not confuse the newer `ColumnOperators.any_()` method with the legacy version of this method, the `Comparator.any()` method that’s specific to `ARRAY`, which uses a different calling style.

  method `sqlalchemy.ext.associationproxy.ColumnAssociationProxyInstance.`asc() → ColumnOperators

    inherited from the `ColumnOperators.asc()` method of `ColumnOperators`

    Produce a `asc()` clause against the parent object.

  attribute `sqlalchemy.ext.associationproxy.ColumnAssociationProxyInstance.`attr

    inherited from the `AssociationProxyInstance.attr` attribute of `AssociationProxyInstance`

    Return a tuple of `(local_attr, remote_attr)`.

    This attribute was originally intended to facilitate using the `Query.join()` method to join across the two relationships at once, however this makes use of a deprecated calling style.

    To use `select.join()` or `Query.join()` with an association proxy, the current method is to make use of the `AssociationProxyInstance.local_attr` and `AssociationProxyInstance.remote_attr` attributes separately:

        stmt = (
            select(Parent).
            join(Parent.proxied.local_attr).
            join(Parent.proxied.remote_attr)
        )

    A future release may seek to provide a more succinct join pattern for association proxy attributes.

    See also

    `AssociationProxyInstance.local_attr`

    `AssociationProxyInstance.remote_attr`

  method `sqlalchemy.ext.associationproxy.ColumnAssociationProxyInstance.`between(cleft: Any, cright: Any, symmetric: bool = False) → ColumnOperators

    inherited from the `ColumnOperators.between()` method of `ColumnOperators`

    Produce a `between()` clause against the parent object, given the lower and upper range.

  method `sqlalchemy.ext.associationproxy.ColumnAssociationProxyInstance.`bitwise_and(other: Any) → ColumnOperators

    inherited from the `ColumnOperators.bitwise_and()` method of `ColumnOperators`

    Produce a bitwise AND operation, typically via the `&` operator.

    New in version 2.0.2.

    See also

    Bitwise Operators

  method `sqlalchemy.ext.associationproxy.ColumnAssociationProxyInstance.`bitwise_lshift(other: Any) → ColumnOperators

    inherited from the `ColumnOperators.bitwise_lshift()` method of `ColumnOperators`

    Produce a bitwise LSHIFT operation, typically via the `<<` operator.

    New in version 2.0.2.

    See also

    Bitwise Operators

  method `sqlalchemy.ext.associationproxy.ColumnAssociationProxyInstance.`bitwise_not() → ColumnOperators

    inherited from the `ColumnOperators.bitwise_not()` method of `ColumnOperators`

    Produce a bitwise NOT operation, typically via the `~` operator.

    New in version 2.0.2.

    See also

    Bitwise Operators

  method `sqlalchemy.ext.associationproxy.ColumnAssociationProxyInstance.`bitwise_or(other: Any) → ColumnOperators

    inherited from the `ColumnOperators.bitwise_or()` method of `ColumnOperators`

    Produce a bitwise OR operation, typically via the `|` operator.

    New in version 2.0.2.

    See also

    Bitwise Operators

  method `sqlalchemy.ext.associationproxy.ColumnAssociationProxyInstance.`bitwise_rshift(other: Any) → ColumnOperators

    inherited from the `ColumnOperators.bitwise_rshift()` method of `ColumnOperators`

    Produce a bitwise RSHIFT operation, typically via the `>>` operator.

    New in version 2.0.2.

    See also

    Bitwise Operators

  method `sqlalchemy.ext.associationproxy.ColumnAssociationProxyInstance.`bitwise_xor(other: Any) → ColumnOperators

    inherited from the `ColumnOperators.bitwise_xor()` method of `ColumnOperators`

    Produce a bitwise XOR operation, typically via the `^` operator, or `#` for PostgreSQL.

    New in version 2.0.2.

    See also

    Bitwise Operators

  method `sqlalchemy.ext.associationproxy.ColumnAssociationProxyInstance.`bool_op(opstring: str, precedence: int = 0, python_impl: Callable[[...], Any] | None = None) → Callable[[Any], Operators]

    inherited from the `Operators.bool_op()` method of `Operators`

    Return a custom boolean operator.

    This method is shorthand for calling `Operators.op()` and passing the `Operators.op.is_comparison` flag with True. A key advantage to using `Operators.bool_op()` is that when using column constructs, the “boolean” nature of the returned expression will be present for PEP 484 purposes.

    See also

    `Operators.op()`

  method `sqlalchemy.ext.associationproxy.ColumnAssociationProxyInstance.`collate(collation: str) → ColumnOperators

    inherited from the `ColumnOperators.collate()` method of `ColumnOperators`

    Produce a `collate()` clause against the parent object, given the collation string.

    See also

    `collate()`

  method `sqlalchemy.ext.associationproxy.ColumnAssociationProxyInstance.`concat(other: Any) → ColumnOperators

    inherited from the `ColumnOperators.concat()` method of `ColumnOperators`

    Implement the ‘concat’ operator.

    In a column context, produces the clause `a || b`, or uses the `concat()` operator on MySQL.

  method `sqlalchemy.ext.associationproxy.ColumnAssociationProxyInstance.`contains(other: Any, **kw: Any) → ColumnOperators

    inherited from the `ColumnOperators.contains()` method of `ColumnOperators`

    Implement the ‘contains’ operator.

    Produces a LIKE expression that tests against a match for the middle of a string value:

        column LIKE '%' || <other> || '%'

    E.g.:

        stmt = select(sometable).\
            where(sometable.c.column.contains("foobar"))

    Since the operator uses `LIKE`, wildcard characters `"%"` and `"_"` that are present inside the <other> expression will behave like wildcards as well. For literal string values, the `ColumnOperators.contains.autoescape` flag may be set to `True` to apply escaping to occurrences of these characters within the string value so that they match as themselves and not as wildcard characters. Alternatively, the `ColumnOperators.contains.escape` parameter will establish a given character as an escape character which can be of use when the target expression is not a literal string.

    Parameters:

      - other – expression to be compared. This is usually a plain string value, but can also be an arbitrary SQL expression. LIKE wildcard characters `%` and `_` are not escaped by default unless the `ColumnOperators.contains.autoescape` flag is set to True.

      - autoescape –

        boolean; when True, establishes an escape character within the LIKE expression, then applies it to all occurrences of `"%"`, `"_"` and the escape character itself within the comparison value, which is assumed to be a literal string and not a SQL expression.

        An expression such as:

            somecolumn.contains("foo%bar", autoescape=True)

        Will render as:

            somecolumn LIKE '%' || :param || '%' ESCAPE '/'

        With the value of `:param` as `"foo/%bar"`.

      - escape –

        a character which when given will render with the `ESCAPE` keyword to establish that character as the escape character. This character can then be placed preceding occurrences of `%` and `_` to allow them to act as themselves and not wildcard characters.

        An expression such as:

            somecolumn.contains("foo/%bar", escape="^")

        Will render as:

            somecolumn LIKE '%' || :param || '%' ESCAPE '^'

        The parameter may also be combined with `ColumnOperators.contains.autoescape`:

            somecolumn.contains("foo%bar^bat", escape="^", autoescape=True)

        Where above, the given literal parameter will be converted to `"foo^%bar^^bat"` before being passed to the database.

    See also

    `ColumnOperators.startswith()`

    `ColumnOperators.endswith()`

    `ColumnOperators.like()`

  method `sqlalchemy.ext.associationproxy.ColumnAssociationProxyInstance.`desc() → ColumnOperators

    inherited from the `ColumnOperators.desc()` method of `ColumnOperators`

    Produce a `desc()` clause against the parent object.

  method `sqlalchemy.ext.associationproxy.ColumnAssociationProxyInstance.`distinct() → ColumnOperators

    inherited from the `ColumnOperators.distinct()` method of `ColumnOperators`

    Produce a `distinct()` clause against the parent object.

  method `sqlalchemy.ext.associationproxy.ColumnAssociationProxyInstance.`endswith(other: Any, escape: str | None = None, autoescape: bool = False) → ColumnOperators

    inherited from the `ColumnOperators.endswith()` method of `ColumnOperators`

    Implement the ‘endswith’ operator.

    Produces a LIKE expression that tests against a match for the end of a string value:

        column LIKE '%' || <other>

    E.g.:

        stmt = select(sometable).\
            where(sometable.c.column.endswith("foobar"))

    Since the operator uses `LIKE`, wildcard characters `"%"` and `"_"` that are present inside the <other> expression will behave like wildcards as well. For literal string values, the `ColumnOperators.endswith.autoescape` flag may be set to `True` to apply escaping to occurrences of these characters within the string value so that they match as themselves and not as wildcard characters. Alternatively, the `ColumnOperators.endswith.escape` parameter will establish a given character as an escape character which can be of use when the target expression is not a literal string.

    Parameters:

      - other – expression to be compared. This is usually a plain string value, but can also be an arbitrary SQL expression. LIKE wildcard characters `%` and `_` are not escaped by default unless the `ColumnOperators.endswith.autoescape` flag is set to True.

      - autoescape –

        boolean; when True, establishes an escape character within the LIKE expression, then applies it to all occurrences of `"%"`, `"_"` and the escape character itself within the comparison value, which is assumed to be a literal string and not a SQL expression.

        An expression such as:

            somecolumn.endswith("foo%bar", autoescape=True)

        Will render as:

            somecolumn LIKE '%' || :param ESCAPE '/'

        With the value of `:param` as `"foo/%bar"`.

      - escape –

        a character which when given will render with the `ESCAPE` keyword to establish that character as the escape character. This character can then be placed preceding occurrences of `%` and `_` to allow them to act as themselves and not wildcard characters.

        An expression such as:

            somecolumn.endswith("foo/%bar", escape="^")

        Will render as:

            somecolumn LIKE '%' || :param ESCAPE '^'

        The parameter may also be combined with `ColumnOperators.endswith.autoescape`:

            somecolumn.endswith("foo%bar^bat", escape="^", autoescape=True)

        Where above, the given literal parameter will be converted to `"foo^%bar^^bat"` before being passed to the database.

    See also

    `ColumnOperators.startswith()`

    `ColumnOperators.contains()`

    `ColumnOperators.like()`

  method `sqlalchemy.ext.associationproxy.ColumnAssociationProxyInstance.`has(criterion: _ColumnExpressionArgument[bool] | None = None, **kwargs: Any) → ColumnElement[bool]

    inherited from the `AssociationProxyInstance.has()` method of `AssociationProxyInstance`

    Produce a proxied ‘has’ expression using EXISTS.

    This expression will be a composed product using the `Comparator.any()` and/or `Comparator.has()` operators of the underlying proxied attributes.

  method `sqlalchemy.ext.associationproxy.ColumnAssociationProxyInstance.`icontains(other: Any, **kw: Any) → ColumnOperators

    inherited from the `ColumnOperators.icontains()` method of `ColumnOperators`

    Implement the `icontains` operator, e.g. case insensitive version of `ColumnOperators.contains()`.

    Produces a LIKE expression that tests against an insensitive match for the middle of a string value:

        lower(column) LIKE '%' || lower(<other>) || '%'

    E.g.:

        stmt = select(sometable).\
            where(sometable.c.column.icontains("foobar"))

    Since the operator uses `LIKE`, wildcard characters `"%"` and `"_"` that are present inside the <other> expression will behave like wildcards as well. For literal string values, the `ColumnOperators.icontains.autoescape` flag may be set to `True` to apply escaping to occurrences of these characters within the string value so that they match as themselves and not as wildcard characters. Alternatively, the `ColumnOperators.icontains.escape` parameter will establish a given character as an escape character which can be of use when the target expression is not a literal string.

    Parameters:

      - other – expression to be compared. This is usually a plain string value, but can also be an arbitrary SQL expression. LIKE wildcard characters `%` and `_` are not escaped by default unless the `ColumnOperators.icontains.autoescape` flag is set to True.

      - autoescape –

        boolean; when True, establishes an escape character within the LIKE expression, then applies it to all occurrences of `"%"`, `"_"` and the escape character itself within the comparison value, which is assumed to be a literal string and not a SQL expression.

        An expression such as:

            somecolumn.icontains("foo%bar", autoescape=True)

        Will render as:

            lower(somecolumn) LIKE '%' || lower(:param) || '%' ESCAPE '/'

        With the value of `:param` as `"foo/%bar"`.

      - escape –

        a character which when given will render with the `ESCAPE` keyword to establish that character as the escape character. This character can then be placed preceding occurrences of `%` and `_` to allow them to act as themselves and not wildcard characters.

        An expression such as:

            somecolumn.icontains("foo/%bar", escape="^")

        Will render as:

            lower(somecolumn) LIKE '%' || lower(:param) || '%' ESCAPE '^'

        The parameter may also be combined with `ColumnOperators.contains.autoescape`:

            somecolumn.icontains("foo%bar^bat", escape="^", autoescape=True)

        Where above, the given literal parameter will be converted to `"foo^%bar^^bat"` before being passed to the database.

    See also

    `ColumnOperators.contains()`

  method `sqlalchemy.ext.associationproxy.ColumnAssociationProxyInstance.`iendswith(other: Any, escape: str | None = None, autoescape: bool = False) → ColumnOperators

    inherited from the `ColumnOperators.iendswith()` method of `ColumnOperators`

    Implement the `iendswith` operator, e.g. case insensitive version of `ColumnOperators.endswith()`.

    Produces a LIKE expression that tests against an insensitive match for the end of a string value:

        lower(column) LIKE '%' || lower(<other>)

    E.g.:

        stmt = select(sometable).\
            where(sometable.c.column.iendswith("foobar"))

    Since the operator uses `LIKE`, wildcard characters `"%"` and `"_"` that are present inside the <other> expression will behave like wildcards as well. For literal string values, the `ColumnOperators.iendswith.autoescape` flag may be set to `True` to apply escaping to occurrences of these characters within the string value so that they match as themselves and not as wildcard characters. Alternatively, the `ColumnOperators.iendswith.escape` parameter will establish a given character as an escape character which can be of use when the target expression is not a literal string.

    Parameters:

      - other – expression to be compared. This is usually a plain string value, but can also be an arbitrary SQL expression. LIKE wildcard characters `%` and `_` are not escaped by default unless the `ColumnOperators.iendswith.autoescape` flag is set to True.

      - autoescape –

        boolean; when True, establishes an escape character within the LIKE expression, then applies it to all occurrences of `"%"`, `"_"` and the escape character itself within the comparison value, which is assumed to be a literal string and not a SQL expression.

        An expression such as:

            somecolumn.iendswith("foo%bar", autoescape=True)

        Will render as:

            lower(somecolumn) LIKE '%' || lower(:param) ESCAPE '/'

        With the value of `:param` as `"foo/%bar"`.

      - escape –

        a character which when given will render with the `ESCAPE` keyword to establish that character as the escape character. This character can then be placed preceding occurrences of `%` and `_` to allow them to act as themselves and not wildcard characters.

        An expression such as:

            somecolumn.iendswith("foo/%bar", escape="^")

        Will render as:

            lower(somecolumn) LIKE '%' || lower(:param) ESCAPE '^'

        The parameter may also be combined with `ColumnOperators.iendswith.autoescape`:

            somecolumn.endswith("foo%bar^bat", escape="^", autoescape=True)

        Where above, the given literal parameter will be converted to `"foo^%bar^^bat"` before being passed to the database.

    See also

    `ColumnOperators.endswith()`

  method `sqlalchemy.ext.associationproxy.ColumnAssociationProxyInstance.`ilike(other: Any, escape: str | None = None) → ColumnOperators

    inherited from the `ColumnOperators.ilike()` method of `ColumnOperators`

    Implement the `ilike` operator, e.g. case insensitive LIKE.

    In a column context, produces an expression either of the form:

        lower(a) LIKE lower(other)

    Or on backends that support the ILIKE operator:

        a ILIKE other

    E.g.:

        stmt = select(sometable).\
            where(sometable.c.column.ilike("%foobar%"))

    Parameters:

      - other – expression to be compared

      - escape –

        optional escape character, renders the `ESCAPE` keyword, e.g.:

            somecolumn.ilike("foo/%bar", escape="/")

    See also

    `ColumnOperators.like()`

  method `sqlalchemy.ext.associationproxy.ColumnAssociationProxyInstance.`in_(other: Any) → ColumnOperators

    inherited from the `ColumnOperators.in_()` method of `ColumnOperators`

    Implement the `in` operator.

    In a column context, produces the clause `column IN <other>`.

    The given parameter `other` may be:

    - A list of literal values, e.g.:

          stmt.where(column.in_([1, 2, 3]))

      In this calling form, the list of items is converted to a set of bound parameters the same length as the list given:

          WHERE COL IN (?, ?, ?)

    - A list of tuples may be provided if the comparison is against a `tuple_()` containing multiple expressions:

          from sqlalchemy import tuple_
          stmt.where(tuple_(col1, col2).in_([(1, 10), (2, 20), (3, 30)]))

    - An empty list, e.g.:

          stmt.where(column.in_([]))

      In this calling form, the expression renders an “empty set” expression. These expressions are tailored to individual backends and are generally trying to get an empty SELECT statement as a subquery. Such as on SQLite, the expression is:

          WHERE col IN (SELECT 1 FROM (SELECT 1) WHERE 1!=1)

      Changed in version 1.4: empty IN expressions now use an execution-time generated SELECT subquery in all cases.

    - A bound parameter, e.g. `bindparam()`, may be used if it includes the `bindparam.expanding` flag:

          stmt.where(column.in_(bindparam('value', expanding=True)))

      In this calling form, the expression renders a special non-SQL placeholder expression that looks like:

          WHERE COL IN ([EXPANDING_value])

      This placeholder expression is intercepted at statement execution time to be converted into the variable number of bound parameter form illustrated earlier. If the statement were executed as:

          connection.execute(stmt, {"value": [1, 2, 3]})

      The database would be passed a bound parameter for each value:

          WHERE COL IN (?, ?, ?)

      New in version 1.2: added “expanding” bound parameters

      If an empty list is passed, a special “empty list” expression, which is specific to the database in use, is rendered. On SQLite this would be:

          WHERE COL IN (SELECT 1 FROM (SELECT 1) WHERE 1!=1)

      New in version 1.3: “expanding” bound parameters now support empty lists

    - a `select()` construct, which is usually a correlated scalar select:

          stmt.where(
              column.in_(
                  select(othertable.c.y).
                  where(table.c.x == othertable.c.x)
              )
          )

      In this calling form, `ColumnOperators.in_()` renders as given:

          WHERE COL IN (SELECT othertable.y
          FROM othertable WHERE othertable.x = table.x)

    Parameters:

      other – a list of literals, a `select()` construct, or a `bindparam()` construct that includes the `bindparam.expanding` flag set to True.

  method `sqlalchemy.ext.associationproxy.ColumnAssociationProxyInstance.`is_(other: Any) → ColumnOperators

    inherited from the `ColumnOperators.is_()` method of `ColumnOperators`

    Implement the `IS` operator.

    Normally, `IS` is generated automatically when comparing to a value of `None`, which resolves to `NULL`. However, explicit usage of `IS` may be desirable if comparing to boolean values on certain platforms.

    See also

    `ColumnOperators.is_not()`

  method `sqlalchemy.ext.associationproxy.ColumnAssociationProxyInstance.`is_distinct_from(other: Any) → ColumnOperators

    inherited from the `ColumnOperators.is_distinct_from()` method of `ColumnOperators`

    Implement the `IS DISTINCT FROM` operator.

    Renders “a IS DISTINCT FROM b” on most platforms; on some such as SQLite may render “a IS NOT b”.

  method `sqlalchemy.ext.associationproxy.ColumnAssociationProxyInstance.`is_not(other: Any) → ColumnOperators

    inherited from the `ColumnOperators.is_not()` method of `ColumnOperators`

    Implement the `IS NOT` operator.

    Normally, `IS NOT` is generated automatically when comparing to a value of `None`, which resolves to `NULL`. However, explicit usage of `IS NOT` may be desirable if comparing to boolean values on certain platforms.

    Changed in version 1.4: The `is_not()` operator is renamed from `isnot()` in previous releases. The previous name remains available for backwards compatibility.

    See also

    `ColumnOperators.is_()`

  method `sqlalchemy.ext.associationproxy.ColumnAssociationProxyInstance.`is_not_distinct_from(other: Any) → ColumnOperators

    inherited from the `ColumnOperators.is_not_distinct_from()` method of `ColumnOperators`

    Implement the `IS NOT DISTINCT FROM` operator.

    Renders “a IS NOT DISTINCT FROM b” on most platforms; on some such as SQLite may render “a IS b”.

    Changed in version 1.4: The `is_not_distinct_from()` operator is renamed from `isnot_distinct_from()` in previous releases. The previous name remains available for backwards compatibility.

  method `sqlalchemy.ext.associationproxy.ColumnAssociationProxyInstance.`isnot(other: Any) → ColumnOperators

    inherited from the `ColumnOperators.isnot()` method of `ColumnOperators`

    Implement the `IS NOT` operator.

    Normally, `IS NOT` is generated automatically when comparing to a value of `None`, which resolves to `NULL`. However, explicit usage of `IS NOT` may be desirable if comparing to boolean values on certain platforms.

    Changed in version 1.4: The `is_not()` operator is renamed from `isnot()` in previous releases. The previous name remains available for backwards compatibility.

    See also

    `ColumnOperators.is_()`

  method `sqlalchemy.ext.associationproxy.ColumnAssociationProxyInstance.`isnot_distinct_from(other: Any) → ColumnOperators

    inherited from the `ColumnOperators.isnot_distinct_from()` method of `ColumnOperators`

    Implement the `IS NOT DISTINCT FROM` operator.

    Renders “a IS NOT DISTINCT FROM b” on most platforms; on some such as SQLite may render “a IS b”.

    Changed in version 1.4: The `is_not_distinct_from()` operator is renamed from `isnot_distinct_from()` in previous releases. The previous name remains available for backwards compatibility.

  method `sqlalchemy.ext.associationproxy.ColumnAssociationProxyInstance.`istartswith(other: Any, escape: str | None = None, autoescape: bool = False) → ColumnOperators

    inherited from the `ColumnOperators.istartswith()` method of `ColumnOperators`

    Implement the `istartswith` operator, e.g. case insensitive version of `ColumnOperators.startswith()`.

    Produces a LIKE expression that tests against an insensitive match for the start of a string value:

        lower(column) LIKE lower(<other>) || '%'

    E.g.:

        stmt = select(sometable).\
            where(sometable.c.column.istartswith("foobar"))

    Since the operator uses `LIKE`, wildcard characters `"%"` and `"_"` that are present inside the <other> expression will behave like wildcards as well. For literal string values, the `ColumnOperators.istartswith.autoescape` flag may be set to `True` to apply escaping to occurrences of these characters within the string value so that they match as themselves and not as wildcard characters. Alternatively, the `ColumnOperators.istartswith.escape` parameter will establish a given character as an escape character which can be of use when the target expression is not a literal string.

    Parameters:

      - other – expression to be compared. This is usually a plain string value, but can also be an arbitrary SQL expression. LIKE wildcard characters `%` and `_` are not escaped by default unless the `ColumnOperators.istartswith.autoescape` flag is set to True.

      - autoescape –

        boolean; when True, establishes an escape character within the LIKE expression, then applies it to all occurrences of `"%"`, `"_"` and the escape character itself within the comparison value, which is assumed to be a literal string and not a SQL expression.

        An expression such as:

            somecolumn.istartswith("foo%bar", autoescape=True)

        Will render as:

            lower(somecolumn) LIKE lower(:param) || '%' ESCAPE '/'

        With the value of `:param` as `"foo/%bar"`.

      - escape –

        a character which when given will render with the `ESCAPE` keyword to establish that character as the escape character. This character can then be placed preceding occurrences of `%` and `_` to allow them to act as themselves and not wildcard characters.

        An expression such as:

            somecolumn.istartswith("foo/%bar", escape="^")

        Will render as:

            lower(somecolumn) LIKE lower(:param) || '%' ESCAPE '^'

        The parameter may also be combined with `ColumnOperators.istartswith.autoescape`:

            somecolumn.istartswith("foo%bar^bat", escape="^", autoescape=True)

        Where above, the given literal parameter will be converted to `"foo^%bar^^bat"` before being passed to the database.

    See also

    `ColumnOperators.startswith()`

  method `sqlalchemy.ext.associationproxy.ColumnAssociationProxyInstance.`like(other: Any, escape: str | None = None) → ColumnOperators

    inherited from the `ColumnOperators.like()` method of `ColumnOperators`

    Implement the `like` operator.

    In a column context, produces the expression:

        a LIKE other

    E.g.:

        stmt = select(sometable).\
            where(sometable.c.column.like("%foobar%"))

    Parameters:

      - other – expression to be compared

      - escape –

        optional escape character, renders the `ESCAPE` keyword, e.g.:

            somecolumn.like("foo/%bar", escape="/")

    See also

    `ColumnOperators.ilike()`

  attribute `sqlalchemy.ext.associationproxy.ColumnAssociationProxyInstance.`local_attr

    inherited from the `AssociationProxyInstance.local_attr` attribute of `AssociationProxyInstance`

    The ‘local’ class attribute referenced by this `AssociationProxyInstance`.

    See also

    `AssociationProxyInstance.attr`

    `AssociationProxyInstance.remote_attr`

  method `sqlalchemy.ext.associationproxy.ColumnAssociationProxyInstance.`match(other: Any, **kwargs: Any) → ColumnOperators

    inherited from the `ColumnOperators.match()` method of `ColumnOperators`

    Implements a database-specific ‘match’ operator.

    `ColumnOperators.match()` attempts to resolve to a MATCH-like function or operator provided by the backend. Examples include:

    - PostgreSQL - renders `x @@ plainto_tsquery(y)`

      > Changed in version 2.0: `plainto_tsquery()` is used instead of `to_tsquery()` for PostgreSQL now; for compatibility with other forms, see Full Text Search.

    - MySQL - renders `MATCH (x) AGAINST (y IN BOOLEAN MODE)`

      See also

      `match` - MySQL specific construct with additional features.

    - Oracle - renders `CONTAINS(x, y)`

    - other backends may provide special implementations.

    - Backends without any special implementation will emit the operator as “MATCH”. This is compatible with SQLite, for example.

  method `sqlalchemy.ext.associationproxy.ColumnAssociationProxyInstance.`not_ilike(other: Any, escape: str | None = None) → ColumnOperators

    inherited from the `ColumnOperators.not_ilike()` method of `ColumnOperators`

    implement the `NOT ILIKE` operator.

    This is equivalent to using negation with `ColumnOperators.ilike()`, i.e. `~x.ilike(y)`.

    Changed in version 1.4: The `not_ilike()` operator is renamed from `notilike()` in previous releases. The previous name remains available for backwards compatibility.

    See also

    `ColumnOperators.ilike()`

  method `sqlalchemy.ext.associationproxy.ColumnAssociationProxyInstance.`not_in(other: Any) → ColumnOperators

    inherited from the `ColumnOperators.not_in()` method of `ColumnOperators`

    implement the `NOT IN` operator.

    This is equivalent to using negation with `ColumnOperators.in_()`, i.e. `~x.in_(y)`.

    In the case that `other` is an empty sequence, the compiler produces an “empty not in” expression. This defaults to the expression “1 = 1” to produce true in all cases. The `create_engine.empty_in_strategy` may be used to alter this behavior.

    Changed in version 1.4: The `not_in()` operator is renamed from `notin_()` in previous releases. The previous name remains available for backwards compatibility.

    Changed in version 1.2: The `ColumnOperators.in_()` and `ColumnOperators.not_in()` operators now produce a “static” expression for an empty IN sequence by default.

    See also

    `ColumnOperators.in_()`

  method `sqlalchemy.ext.associationproxy.ColumnAssociationProxyInstance.`not_like(other: Any, escape: str | None = None) → ColumnOperators

    inherited from the `ColumnOperators.not_like()` method of `ColumnOperators`

    implement the `NOT LIKE` operator.

    This is equivalent to using negation with `ColumnOperators.like()`, i.e. `~x.like(y)`.

    Changed in version 1.4: The `not_like()` operator is renamed from `notlike()` in previous releases. The previous name remains available for backwards compatibility.

    See also

    `ColumnOperators.like()`

  method `sqlalchemy.ext.associationproxy.ColumnAssociationProxyInstance.`notilike(other: Any, escape: str | None = None) → ColumnOperators

    inherited from the `ColumnOperators.notilike()` method of `ColumnOperators`

    implement the `NOT ILIKE` operator.

    This is equivalent to using negation with `ColumnOperators.ilike()`, i.e. `~x.ilike(y)`.

    Changed in version 1.4: The `not_ilike()` operator is renamed from `notilike()` in previous releases. The previous name remains available for backwards compatibility.

    See also

    `ColumnOperators.ilike()`

  method `sqlalchemy.ext.associationproxy.ColumnAssociationProxyInstance.`notin_(other: Any) → ColumnOperators

    inherited from the `ColumnOperators.notin_()` method of `ColumnOperators`

    implement the `NOT IN` operator.

    This is equivalent to using negation with `ColumnOperators.in_()`, i.e. `~x.in_(y)`.

    In the case that `other` is an empty sequence, the compiler produces an “empty not in” expression. This defaults to the expression “1 = 1” to produce true in all cases. The `create_engine.empty_in_strategy` may be used to alter this behavior.

    Changed in version 1.4: The `not_in()` operator is renamed from `notin_()` in previous releases. The previous name remains available for backwards compatibility.

    Changed in version 1.2: The `ColumnOperators.in_()` and `ColumnOperators.not_in()` operators now produce a “static” expression for an empty IN sequence by default.

    See also

    `ColumnOperators.in_()`

  method `sqlalchemy.ext.associationproxy.ColumnAssociationProxyInstance.`notlike(other: Any, escape: str | None = None) → ColumnOperators

    inherited from the `ColumnOperators.notlike()` method of `ColumnOperators`

    implement the `NOT LIKE` operator.

    This is equivalent to using negation with `ColumnOperators.like()`, i.e. `~x.like(y)`.

    Changed in version 1.4: The `not_like()` operator is renamed from `notlike()` in previous releases. The previous name remains available for backwards compatibility.

    See also

    `ColumnOperators.like()`

  method `sqlalchemy.ext.associationproxy.ColumnAssociationProxyInstance.`nulls_first() → ColumnOperators

    inherited from the `ColumnOperators.nulls_first()` method of `ColumnOperators`

    Produce a `nulls_first()` clause against the parent object.

    Changed in version 1.4: The `nulls_first()` operator is renamed from `nullsfirst()` in previous releases. The previous name remains available for backwards compatibility.

  method `sqlalchemy.ext.associationproxy.ColumnAssociationProxyInstance.`nulls_last() → ColumnOperators

    inherited from the `ColumnOperators.nulls_last()` method of `ColumnOperators`

    Produce a `nulls_last()` clause against the parent object.

    Changed in version 1.4: The `nulls_last()` operator is renamed from `nullslast()` in previous releases. The previous name remains available for backwards compatibility.

  method `sqlalchemy.ext.associationproxy.ColumnAssociationProxyInstance.`nullsfirst() → ColumnOperators

    inherited from the `ColumnOperators.nullsfirst()` method of `ColumnOperators`

    Produce a `nulls_first()` clause against the parent object.

    Changed in version 1.4: The `nulls_first()` operator is renamed from `nullsfirst()` in previous releases. The previous name remains available for backwards compatibility.

  method `sqlalchemy.ext.associationproxy.ColumnAssociationProxyInstance.`nullslast() → ColumnOperators

    inherited from the `ColumnOperators.nullslast()` method of `ColumnOperators`

    Produce a `nulls_last()` clause against the parent object.

    Changed in version 1.4: The `nulls_last()` operator is renamed from `nullslast()` in previous releases. The previous name remains available for backwards compatibility.

  method `sqlalchemy.ext.associationproxy.ColumnAssociationProxyInstance.`op(opstring: str, precedence: int = 0, is_comparison: bool = False, return_type: Type[TypeEngine[Any]] | TypeEngine[Any] | None = None, python_impl: Callable[..., Any] | None = None) → Callable[[Any], Operators]

    inherited from the `Operators.op()` method of `Operators`

    Produce a generic operator function.

    e.g.:

        somecolumn.op("*")(5)

    produces:

        somecolumn * 5

    This function can also be used to make bitwise operators explicit. For example:

        somecolumn.op('&')(0xff)

    is a bitwise AND of the value in `somecolumn`.

    Parameters:

      - opstring – a string which will be output as the infix operator between this element and the expression passed to the generated function.

      - precedence –

        precedence which the database is expected to apply to the operator in SQL expressions. This integer value acts as a hint for the SQL compiler to know when explicit parenthesis should be rendered around a particular operation. A lower number will cause the expression to be parenthesized when applied against another operator with higher precedence. The default value of `0` is lower than all operators except for the comma (`,`) and `AS` operators. A value of 100 will be higher or equal to all operators, and -100 will be lower than or equal to all operators.

        See also

        I’m using op() to generate a custom operator and my parenthesis are not coming out correctly - detailed description of how the SQLAlchemy SQL compiler renders parenthesis

      - is_comparison –

        legacy; if True, the operator will be considered as a “comparison” operator, that is which evaluates to a boolean true/false value, like `==`, `>`, etc. This flag is provided so that ORM relationships can establish that the operator is a comparison operator when used in a custom join condition.

        Using the `is_comparison` parameter is superseded by using the `Operators.bool_op()` method instead; this more succinct operator sets this parameter automatically, but also provides correct PEP 484 typing support as the returned object will express a “boolean” datatype, i.e. `BinaryExpression[bool]`.

      - return_type – a `TypeEngine` class or object that will force the return type of an expression produced by this operator to be of that type. By default, operators that specify `Operators.op.is_comparison` will resolve to `Boolean`, and those that do not will be of the same type as the left-hand operand.

      - python_impl –

        an optional Python function that can evaluate two Python values in the same way as this operator works when run on the database server. Useful for in-Python SQL expression evaluation functions, such as for ORM hybrid attributes, and the ORM “evaluator” used to match objects in a session after a multi-row update or delete.

        e.g.:

            >>> expr = column('x').op('+', python_impl=lambda a, b: a + b)('y')

        The operator for the above expression will also work for non-SQL left and right objects:

            >>> expr.operator(5, 10)
            15

        New in version 2.0.

    See also

    `Operators.bool_op()`

    Redefining and Creating New Operators

    Using custom operators in join conditions

  method `sqlalchemy.ext.associationproxy.ColumnAssociationProxyInstance.`operate(op: OperatorType, *other: Any, **kwargs: Any) → ColumnElement[Any]

    Operate on an argument.

    This is the lowest level of operation, raises `NotImplementedError` by default.

    Overriding this on a subclass can allow common behavior to be applied to all operations. For example, overriding `ColumnOperators` to apply `func.lower()` to the left and right side:

        class MyComparator(ColumnOperators):
            def operate(self, op, other, **kwargs):
                return op(func.lower(self), func.lower(other), **kwargs)

    Parameters:

      - op – Operator callable.

      - *other – the ‘other’ side of the operation. Will be a single scalar for most operations.

      - **kwargs – modifiers. These may be passed by special operators such as `ColumnOperators.contains()`.

  method `sqlalchemy.ext.associationproxy.ColumnAssociationProxyInstance.`regexp_match(pattern: Any, flags: str | None = None) → ColumnOperators

    inherited from the `ColumnOperators.regexp_match()` method of `ColumnOperators`

    Implements a database-specific ‘regexp match’ operator.

    E.g.:

        stmt = select(table.c.some_column).where(
            table.c.some_column.regexp_match('^(b|c)')
        )

    `ColumnOperators.regexp_match()` attempts to resolve to a REGEXP-like function or operator provided by the backend, however the specific regular expression syntax and flags available are not backend agnostic.

    Examples include:

    - PostgreSQL - renders `x ~ y` or `x !~ y` when negated.

    - Oracle - renders `REGEXP_LIKE(x, y)`

    - SQLite - uses SQLite’s `REGEXP` placeholder operator and calls into the Python `re.match()` builtin.

    - other backends may provide special implementations.

    - Backends without any special implementation will emit the operator as “REGEXP” or “NOT REGEXP”. This is compatible with SQLite and MySQL, for example.

    Regular expression support is currently implemented for Oracle, PostgreSQL, MySQL and MariaDB. Partial support is available for SQLite. Support among third-party dialects may vary.

    Parameters:

      - pattern – The regular expression pattern string or column clause.

      - flags – Any regular expression string flags to apply, passed as plain Python string only. These flags are backend specific. Some backends, like PostgreSQL and MariaDB, may alternatively specify the flags as part of the pattern. When using the ignore case flag ‘i’ in PostgreSQL, the ignore case regexp match operator `~*` or `!~*` will be used.

    New in version 1.4.

    Changed in version 1.4.48,: 2.0.18 Note that due to an implementation error, the “flags” parameter previously accepted SQL expression objects such as column expressions in addition to plain Python strings. This implementation did not work correctly with caching and was removed; strings only should be passed for the “flags” parameter, as these flags are rendered as literal inline values within SQL expressions.

    See also

    `ColumnOperators.regexp_replace()`

  method `sqlalchemy.ext.associationproxy.ColumnAssociationProxyInstance.`regexp_replace(pattern: Any, replacement: Any, flags: str | None = None) → ColumnOperators

    inherited from the `ColumnOperators.regexp_replace()` method of `ColumnOperators`

    Implements a database-specific ‘regexp replace’ operator.

    E.g.:

        stmt = select(
            table.c.some_column.regexp_replace(
                'b(..)',
                'XY',
                flags='g'
            )
        )

    `ColumnOperators.regexp_replace()` attempts to resolve to a REGEXP_REPLACE-like function provided by the backend, that usually emit the function `REGEXP_REPLACE()`. However, the specific regular expression syntax and flags available are not backend agnostic.

    Regular expression replacement support is currently implemented for Oracle, PostgreSQL, MySQL 8 or greater and MariaDB. Support among third-party dialects may vary.

    Parameters:

      - pattern – The regular expression pattern string or column clause.

      - pattern – The replacement string or column clause.

      - flags – Any regular expression string flags to apply, passed as plain Python string only. These flags are backend specific. Some backends, like PostgreSQL and MariaDB, may alternatively specify the flags as part of the pattern.

    New in version 1.4.

    Changed in version 1.4.48,: 2.0.18 Note that due to an implementation error, the “flags” parameter previously accepted SQL expression objects such as column expressions in addition to plain Python strings. This implementation did not work correctly with caching and was removed; strings only should be passed for the “flags” parameter, as these flags are rendered as literal inline values within SQL expressions.

    See also

    `ColumnOperators.regexp_match()`

  attribute `sqlalchemy.ext.associationproxy.ColumnAssociationProxyInstance.`remote_attr

    inherited from the `AssociationProxyInstance.remote_attr` attribute of `AssociationProxyInstance`

    The ‘remote’ class attribute referenced by this `AssociationProxyInstance`.

    See also

    `AssociationProxyInstance.attr`

    `AssociationProxyInstance.local_attr`

  method `sqlalchemy.ext.associationproxy.ColumnAssociationProxyInstance.`reverse_operate(op: OperatorType, other: Any, **kwargs: Any) → Operators

    inherited from the `Operators.reverse_operate()` method of `Operators`

    Reverse operate on an argument.

    Usage is the same as `operate()`.

  attribute `sqlalchemy.ext.associationproxy.ColumnAssociationProxyInstance.`scalar

    inherited from the `AssociationProxyInstance.scalar` attribute of `AssociationProxyInstance`

    Return `True` if this `AssociationProxyInstance` proxies a scalar relationship on the local side.

  method `sqlalchemy.ext.associationproxy.ColumnAssociationProxyInstance.`startswith(other: Any, escape: str | None = None, autoescape: bool = False) → ColumnOperators

    inherited from the `ColumnOperators.startswith()` method of `ColumnOperators`

    Implement the `startswith` operator.

    Produces a LIKE expression that tests against a match for the start of a string value:

        column LIKE <other> || '%'

    E.g.:

        stmt = select(sometable).\
            where(sometable.c.column.startswith("foobar"))

    Since the operator uses `LIKE`, wildcard characters `"%"` and `"_"` that are present inside the <other> expression will behave like wildcards as well. For literal string values, the `ColumnOperators.startswith.autoescape` flag may be set to `True` to apply escaping to occurrences of these characters within the string value so that they match as themselves and not as wildcard characters. Alternatively, the `ColumnOperators.startswith.escape` parameter will establish a given character as an escape character which can be of use when the target expression is not a literal string.

    Parameters:

      - other – expression to be compared. This is usually a plain string value, but can also be an arbitrary SQL expression. LIKE wildcard characters `%` and `_` are not escaped by default unless the `ColumnOperators.startswith.autoescape` flag is set to True.

      - autoescape –

        boolean; when True, establishes an escape character within the LIKE expression, then applies it to all occurrences of `"%"`, `"_"` and the escape character itself within the comparison value, which is assumed to be a literal string and not a SQL expression.

        An expression such as:

            somecolumn.startswith("foo%bar", autoescape=True)

        Will render as:

            somecolumn LIKE :param || '%' ESCAPE '/'

        With the value of `:param` as `"foo/%bar"`.

      - escape –

        a character which when given will render with the `ESCAPE` keyword to establish that character as the escape character. This character can then be placed preceding occurrences of `%` and `_` to allow them to act as themselves and not wildcard characters.

        An expression such as:

            somecolumn.startswith("foo/%bar", escape="^")

        Will render as:

            somecolumn LIKE :param || '%' ESCAPE '^'

        The parameter may also be combined with `ColumnOperators.startswith.autoescape`:

            somecolumn.startswith("foo%bar^bat", escape="^", autoescape=True)

        Where above, the given literal parameter will be converted to `"foo^%bar^^bat"` before being passed to the database.

    See also

    `ColumnOperators.endswith()`

    `ColumnOperators.contains()`

    `ColumnOperators.like()`

  attribute `sqlalchemy.ext.associationproxy.ColumnAssociationProxyInstance.`target_class: Type[Any]

    The intermediary class handled by this `AssociationProxyInstance`.

    Intercepted append/set/assignment events will result in the generation of new instances of this class.

  attribute `sqlalchemy.ext.associationproxy.ColumnAssociationProxyInstance.`timetuple: Literal[None] = None

    inherited from the `ColumnOperators.timetuple` attribute of `ColumnOperators`

    Hack, allows datetime objects to be compared on the LHS.

class sqlalchemy.ext.associationproxy.AssociationProxyExtensionType

  An enumeration.

  Members

  ASSOCIATION_PROXY

  Class signature

  class `sqlalchemy.ext.associationproxy.AssociationProxyExtensionType` (`sqlalchemy.orm.base.InspectionAttrExtensionType`)

  attribute `sqlalchemy.ext.associationproxy.AssociationProxyExtensionType.`ASSOCIATION_PROXY = 'ASSOCIATION_PROXY'

    Symbol indicating an `InspectionAttr` that’s of type `AssociationProxy`.

    Is assigned to the `InspectionAttr.extension_type` attribute.