MDAC 2.5 SDK - ODBC Programmer's Reference
Chapter 4: ODBC Fundamentals
ODBC drivers give the application access to diverse data sources. Each driver lets the application determine at run time what ODBC capabilities and what SQL grammar the driver and each data source supports. This is not a requirement of applications designed to work with a single driver or a small, known set of drivers, because these applications can simply be written to the capabilities of that driver or drivers. To help applications discover driver and data source capabilities, two areas of conformance are available: the ODBC interface and SQL grammar.