How does Oracle act as ODBC and give examples of front end uses with ODBC?

ODBC achieve portability at the level of the executable by introducing an extra level of indirection. All direct interaction with a specific DBMS happens through a DBMS- specific driver. A driver is a software program that translates the ODBC calls into DBMS- specific calls. Drivers are loaded dynamically on demand since the DBMSs the application is going to access are known only at run-time. Available drivers are registered
with a driver manager. The Oracle database driver translates the SQL commands from the application into equivalent commands that the Oracle DBMS understands and takes the result from the DBMS and translate into equivalent form for the application.

Example: Let there be a DSN named EMPLOYEE through, which we want to access the
Oracle database in Visual Basic.
Dim CN As New ADODB.Connection
Dim RS As New ADODB.Recordset
CN.Open "DSN=employee", "scott", "tiger"