The original ODBC uses two sets of data types: SQL data types and C data types. SQL data types are used in the data source, and C data types are used in the C code of the application. The f90SQL interface to ODBC replaces C data types with Fortran data types, which facilitates the task for Fortran programmers.
To describe SQL and Fortran data types, f90SQL defines two sets of type identifiers; SQL and Fortran data type identifiers. The next sections describe these identifiers in detail.