Connecting to a Backup Tnsnames File (Tnsnames File Failover)

The DataDirect Connect for ODBC Oracle Wire Protocol driver and the DataDirect Connect for .NET Oracle data provider allow you to use information from an Oracle tnsnames.ora file to connect to your database. Using an Oracle tnsnames.ora file to centralize connection information in your Oracle environment simplifies maintenance when changes occur. If, however, the tnsnames.ora file is unavailable because, for example, of a hardware failure or traffic overload, then it is useful to be able to open a backup version of the tnsnames.ora file (tnsnames file failover). You can specify one or more backup, or alternate, tnsnames.ora files.

The TNSNamesFile connection string attribute (TNSNames File option for .NET) specifies the fully qualified path to the tnsnames.ora file. To specify multiple locations for the tnsnames.ora file, separate the paths with a comma and enclose them in parentheses, for example:

TNSNamesFile=(F:\server2\oracle\tnsnames.ora,

C:\oracle\product\10.1.0\db_1\network\admin\tnsnames.ora)

The driver or data provider tries to open the first file in the list. If that file is not available, then it tries to open the second file in the list, and so on. This is a valuable backup feature that helps prevent lost productivity if the primary tnsnames.ora file is unavailable.

For a more detailed configuration information, see the DataDirect Connect for ODBC User's Guide and Reference or the DataDirect Connect for .NET User's Guide and Reference.