Open Database Connectivity (ODBC) is a Call-Level Interface (CLI) that allows C and C++ applications to access data from ODBC data sources. A CLI is an API consisting of functions an application calls to obtain a set of services. ODBC data sources include data stored in different formats, not just SQL databases. An application uses an ODBC driver to access a data source. An ODBC driver is a DLL that accepts calls to the ODBC API functions and does whatever is necessary to process that request against the data source.
ODBC is aligned with these specifications and standards defining a CLI for data access:
ODBC has been widely accepted by database programmers, and several database vendors or third-party companies supply ODBC drivers. Several other Microsoft data access APIs were defined as simplified object models over ODBC:
Microsoft® SQL Server™ includes a native Microsoft SQL Server ODBC driver that can be used by ODBC applications to access the data in SQL Server. The SQL Server ODBC Driver complies with Level 2 of the ODBC 3.51 specification and exposes all the features of SQL Server. In SQL Server version 7.0 all of the SQL Server utilities except isql use the ODBC API and the SQL Server ODBC Driver.
ODBC can be used in tools, utilities, or system level development needing either top performance or access to SQL Server features, and which are not COM applications. ODBC, like OLE DB, allows individual drivers to define driver-specific mechanisms to support additional features of the data engine accessed by the driver. These features include: