ORA-12323: unable to open database (link name string)
Cause: This message should be accompanied by additional error messages that indicate the cause of the problem.
Action: Follow the steps outlined in the accompanying error messages to resolve the problem.
ORA-12322: unable to mount database (link name string)
Cause: This message should be accompanied by additional error messages that indicate the cause of the problem.
Action: Follow the steps outlined in the accompanying error messages to resolve the problem.
ORA-12321: database (link name string) is not open and AUTO_MOUNTING=FALSE
Cause: The secondary database that your instance is attempting to mount is not open and automatic mounting has not been enabled.
Action: Manually mount and open the secondary database using ALTER DATABASE with the OPEN and MOUNT options. Alternately, to allow your instance to automatically mount and open secondary databases, set the AUTO_MOUNTING parameter in the parameter file to TRUE.
ORA-12319: database (link name string) is already open
Cause: You are attempting to open a secondary database that is already open.
Action: The database is open and you need not take additional action to establish access.
ORA-12318: database (link name string) is already mounted
Cause: You are attempting to mount a secondary database that has already been mounted by your instance.
Action: to mount it. To establish access, use the ALTER DATABASE OPEN command to open the database.
ORA-12317: logon to database (link name string) denied
Cause: There are several possible causes for this error. First, you can get this error if your username (and password, if you are using database instead of operating system authentication) in the secondary database are not identical to your username (and password) in the primary database. Second, you can get this error if your username in the secondary database is invalid (has not been created). Third, you can get this error if the username/password combination specified in the connect string of the database link definition is invalid (either not created or has an invalid password).
Action: In the first case, ensure that the secondary database contains a username (and password, if you are using database authentication) identical to the one you are using in the primary database. In general, you should always use operating system authentication in Trusted ORACLE (see the Trusted ORACLE RDBMS Guide to Security Features for more information about the advantages of OS authentication). In the second case, ensure that your username in the secondary database has been created. In the third case, ensure that the username specified in the connect string has been created in the secondary database.
ORA-12316: syntax error in database link’s connect string
Cause: The connect string in the CREATE DATABASE LINK statement has a syntactical error.
Action: Drop the database link and recreate it using valid syntax. See the SQL Language Reference Manual for more information about the connect string portion of the CREATE DATABASE LINK statement.
ORA-12315: database link type is invalid for the ALTER DATABASE statement
Cause: The database link name you specified on the ALTER DATABASE statement is not an ROM: link. You must specify an ROM: link when using the ALTER DATABASE statement to mount or open a secondary database.
Action: Re-issue the ALTER DATABASE statement using a valid ROM: link to the database you want to mount or open. If a valid ROM: link does not exist, create one using the CREATE DATABASE LINK command. See the Trusted ORACLE RDBMS Guide to Security Features for more information about creating database links using the ROM: link type.
ORA-12236: TNS:protocol support not loaded
Cause: On some platforms (such as Windows) protocol support is loaded at run-time. If the shared library (or DLL) for the protocol adapter has not been loaded, then this error is returned.
Action: For further details, turn on tracing and reexecute the operation. The trace file will have the name of the shared library (or DLL) that has not been loaded.
ORA-12235: TNS:Failure to redirect to destination
Cause: This error is reported by an interchange which fails to redirect a connection to another interchange along the path to the destination.
Action: Report the problem to your Network Administrator so that he may fix the problem.