MDAC 2.5 SDK - ODBC Programmer's Reference
Chapter 17: Programming Considerations

Types of Drivers

ODBC drivers can be classified as follows:

• 32-bit ODBC 2.x driver. A 32-bit driver that:
  • Exports only ODBC 2.x functions.
    
    
  • Exhibits ODBC 2.x behavior for behavioral changes.
• ISO and X/Open–compliant driver. A 32-bit driver that:
  • Exports all functions that are documented in the X/Open or ISO CLI documents. This will include some of functions that are deprecated in ODBC.
    
    
  • Exhibits ODBC 3.0 behavior for behavioral changes.
    
    
  • Does not necessarily go through the ODBC 3.0 Driver Manager.
• ODBC 3.0 driver. A 32-bit driver that:
  • Exports only functions that are in ODBC 3.0 minus deprecated functions.
    
    
  • Is capable of exhibiting ODBC 2.x behavior or ODBC 3.0 behavior with respect to behavioral changes, based on the SQL_ATTR_APP_ODBC_VERSION environment attribute.
• ODBC 3.5 (or higher) ANSI driver. A 32-bit driver that:
  • Exports only functions that are in ODBC 3.5 minus deprecated functions.
    
    
  • Is capable of exhibiting ODBC 2.x behavior or ODBC 3.0 behavior, or ODBC 3.5 behavior with respect to behavioral changes, based on the SQL_ATTR_APP_ODBC_VERSION environment attribute.
• ODBC 3.5 (or higher) Unicode driver. A 32-bit driver that:
  • Supports all the features of an ODBC 3.5 ANSI driver.
    
    
  • Exports Unicode versions of all ODBC string APIs.
    
    
  • Can store and process Unicode data on the data source.

Note   16-bit ODBC drivers will not work directly with the ODBC 3.x Driver Manager. However, it is possible for 16-bit drivers to work with the 2.0 ODBC Driver Manager, which subsequently thunks up to the 3.x Driver Manager.