The ODBC driver fits in as a layer of “middleware” in the ODBC architecture, which includes the following components:
An ODBC application is any program that calls ODBC functions and uses them to issue SQL statements. Many vendors have added ODBC support to their existing Windows-based tools so those tools can use ODBC for data access.
ODBC Driver Manager
On Windows platforms, the ODBC driver manager is a Microsoft-supplied dynamic-link library (DLL). On UNIX platforms, the ODBC driver manager is avendor-supplied shared library. The driver manager routes calls from an application to the ODBC driver. To an application, the ODBC driver manager and the driver are a single entity that processes requests to the database. The ODBC driver manager loads the requested driver in response to an application’s call to the ODBC SQLConnect or SQLDriverConnect functions.
An ODBC driver is a dynamic link library (DLL) or a shared library that processes ODBC function calls for a specific data source. The driver connects to the data source, translates the standard SQL statements into syntax the data source can process, and returns data to the application. There are ODBC drivers for every major database system.
A data source is a combination of a database system, the operating system it uses, and any network software required to access it. ODBC defines a database system (DBMS) as any vendor’s implementation of a data access system that provides an SQL interface.