QueryDB

description:- connection description for remote database not found cause:- An attempt was made to connect or log in to a remote database using a connection description that could not be found.or name of Db link is not correct in query. Action:-Specify an existing database link. Query the data dictionary to see all existing database links. See your operating system-specific Net8 documentation for valid connection descriptors.or verify name of db link and name in the query and make changes accordingly

Description : rollback segment string specified not available Error Cause: Either: 1) An attempt was made to bring a rollback segment online that is unavailable during startup; for example, the rollback segment is in an offline tablespace. 2) An attempt was made to bring a rollback segment online that is already online. This is because the rollback segment is specified twice in the ROLLBACK_SEGMENTS parameter in the initialization parameter file or the rollback segment is already online by another instance. 3) An attempt was made to drop a rollback segment that is currently online. 4) An attempt was made to alter a rollback segment that is currently online to use unlimited extents. 5) An attempt was made to online a rollback segment that is corrupted. This is because the rollback is specified in _corrupted_rollback_segments parameter in initialization parameter file. solution: Either: 1) Make the rollback segment available; for example, bring an offline tablespace online. 2) Remo

Cause:- Conflicting export modes were specified. Action:-Specify only one parameter and retry.

SOLUTION: - search ‘ sqlnet.ora ’ Files and make changes as follows:- Original Entry - SQLNET.AUTHENTICATION_SERVICES= (NTS) Modified Entry - SQLNET.AUTHENTICATION_SERVICES= (NONE)

CAUSE:- If DBlink(database link) is not properly configured.or                 the listener is not running.  REMEDIES:-Alter Dblink. or Start the Listener on the machine                     set ORACLE_HOME= cd %ORACLE_HOME%/bin                     lsnrctl start LISTENER                      > lsnrctl start