Pseudo-type Identifiers

For application programming convenience, ODBC defines a number of pseudo type identifiers. These identifiers do not correspond to actual data types, but instead resolve to existing data types depending on the situation.

If an application specifies SQL_F_DEFAULT in f90SQLBindCol, f90SQLGetData, or f90SQLBindParameter, the driver assumes the Fortran data type of the output or input buffer corresponds to the SQL data type of the column or parameter to which the buffer is bound.

Important: Interoperable applications should not use SQL_F_DEFAULT. Instead, they should always specify the Fortran type of the buffer they are using. The reason for this is that drivers cannot always correctly determine the default Fortran type for the following reasons:

• If the DBMS promotes an SQL data type of a column or parameter, the driver cannot determine the original SQL data type of the column or parameter. Therefore, it cannot determine the corresponding default Fortran data type.

• If the driver cannot determine whether a particular column or parameter is signed, as is often the case when this is handled by the DBMS, it cannot determine whether the corresponding default Fortran data type should be signed or unsigned.

Because SQL_F_DEFAULT is provided only as a programming convenience, the application does not lose any functionality when it specifies the actual Fortran data type. Appendix 3 shows the default Fortran data type for each SQL data type.