The description of a column.

Fields are Nothing if the database backend cannot supply the requested information.

The colSize field works like this:

For character types, the maximum width of the column. For numeric types, the total number of digits allowed. See the ODBC manual for more.

The colOctetLength field is defined for character and binary types, and gives the number of bytes the column requires, regardless of encoding.

The type identifier for a given column.

This represents the type of data stored in the column in the underlying SQL engine. It does not form the entire column type; see SqlColDesc for that.

These types correspond mainly to those defined by ODBC.