Open DataBase Connectivity
The Open DataBase Connectivity (ODBC) is actually an Application Programming Interface (API) specification developed by Microsoft. Because ODBC provides a standard interface to both the application program and the backend server, it allows any ODBC-compliant application to connect to any ODBC-compliant database. ODBC has been implemented for Oracle in two ways:
- Native mode ODBC
The ODBC driver duplicates the functionality of SQL*Net, so a client running an ODBC driver can connect to a server running SQL*Net without actually running SQL*Net software on the client machine. Thus, the ODBC driver is able to emulate SQL*Net. This capability is not provided by Oracle, but is implemented by other vendors of ODBC drivers.
- SQL*Net integrated
The ODBC driver provides an interface to SQL*Net that, in turn, actually carries the data to the target node. This is the more common implementation of ODBC, where the ODBC layer actually sits on top of SQL*Net.
Because many applications have been built to interface with ODBC, this technology allows a wide range of applications to connect to an Oracle database without the need to provide a native SQL*Net interface. However, because ODBC relies on SQL*Net for its underlying transport, communications using ODBC are typically less efficient than native SQL*Net. In addition, some Oracle functionality is not fully supported by ODBC drivers. This lack of functionality is easily mistaken for an application problem, and may be difficult to detect and correct. If full Oracle functionality is required, use the Oracle Call Interface (OCI), rather than ODBC.