Programmer Guide : Minimum SQL grammar requirements for ODBC : Data type support
  
Data type support
At minimum, ODBC drivers must support either SQL_CHAR or SQL_VARCHAR.
Other data types support is determined by the driver’s or data source’s SQL-92 conformance level. To determine the SQL-92 conformance level for a driver or data source, applications need to call SQLGetTypeInfo.
See also
Minimum SQL grammar requirements for ODBC