ODBC is a standard definition of an application programming interface (API) used to access data in relational or indexed sequential access method (ISAM) databases. SQL Server supports ODBC, via the SQL Server Native Client ODBC driver, as one of the native APIs for writing C and C++ applications that communicate with SQL Server.
SQL Server programs that are written using the SQL Server Native Client ODBC driver communicate with SQL Server through C function calls. The SQL Server-specific versions of the ODBC functions are implemented in the SQL Server Native Client ODBC driver. The driver passes SQL statements to SQL Server and returns the results of the statements to the application.
The SQL Server Native Client ODBC driver complies with the Microsoft Win32 ODBC 3.51 specification. The driver supports applications written using earlier versions of ODBC in the manner defined in the ODBC 3.51 specification.