ODBC is a native interface that is accessed through a language that can make calls into a native library. In case of the Windows platform, this library is a DLL. Microsoft Windows was the first to provide an ODBC product. Now versions exist for UNIX, OS/2, and Macintosh platforms as well.
In addition to the ODBC software, a separate module or driver is needed for each database to be accessed. The functions in the ODBC API are implemented by these DBMS-specific drivers. ODBC allows programs to use SQL requests that will access databases without having to know the proprietary interfaces to the databases. It handles the SQL request and converts it into a request the individual database system understands.
Most current DBMSs support ODBC which means that computer programs that rely on ODBC can connect to several different brands of DBMSs using the same basic code.
A JDBC-ODBC Bridge is a JDBC driver which employs the ODBC driver to connect to the database. This driver translates JDBC method calls into ODBC function calls. The bridge is usually used when there is no JDBC driver available for a particular database.