What Does Oracle Error message ORA-12154 Mean?

Posted on 2014-09-23
Last Modified: 2014-09-25
I am not familiar with Oracle and have been tasked to attempt to get an application running that uses Oracle.  The application is POCA from the FDA.  This application is old and the documentation (from 2010) refers to Oracle database 10g.  I was only able to get 11g so I know there may be issues.  I was able to install Oracle and am attempting to run the installation scripts for the application.  At one point I get the following error message.

IMP-00058: ORACLE error 12154 encountered
ORA-12154: TNS:could not resolve the connect identifier specified
IMP-00000: Import terminated unsuccessfully

Any idea what this mean?
Question by:rpcr
    LVL 76

    Expert Comment

    by:slightwv (䄆 Netminder)
    The online docs is always a great place to start with error messages:

    When you installed Oracle did you create the necessary entries in the tnsnames.ora file?

    It is probably best that you copy a known good one from another machine.

    This file is in the $ORACLE_HOME/network/admin

    Author Comment

    Thanks for the info slightwv.  I installed Oracle by going through the installation wizard from the Oracle 11g download.  I did not manually create entries in the tnsnames.ora file.  I don't even know what that is as I am not familiar with Oracle.  I'm just trying to get a standalone app that uses Oracle to work if possible.  We are a SQL Server shop so there are no other machines with Oracle installed.

    I'll take a look at the online docs.  Thanks.
    LVL 76

    Accepted Solution

    The tnsnames.ora file is what tells the 'client' where the databases are.

    I places 'client' in quotes because even the database server has the 'client' built in and thus, a tnsnames.ora file.  Oracle was client-server long before it was the cool thing to do.

    Since you aren't familiar with Oracle, I would strongly suggest you not try to manually edit the tnsnames.ora file.  Oracle is pretty picky about the format.

    There are utilities like the Newtowrk Configuration Assistant (netca) that provides a GUI interface to those files.  The bad news here, if you aren't familiar with what you are configuring, the GUIs are confusing.

    Best to just copy known good files around...

    The other semi-important client side file that works with the tnsnames.ora file is the sqlnet.ora file.  They sort of work together but you can live w/o the sqlnet.ora file at times.
    LVL 34

    Expert Comment

    In case it helps you feel any better, getting the TNS configuration entries correct (in the tnsnames.ora file) is usually the most challenging part of setting up a new Oracle server.  Until that is correct, nothing that uses Oracle will work.

    The error message from Oracle's import utility indicates that you are trying to import data from a previous Oracle database into your new database.  This will only work if your new database is installed correctly, configured (in the tnsnames.ora file and in the spfile for managing how Oracles uses memory) and started.  Usually you also need to have the Oracle listener started also.  This executable is separate from the database executable, but is required to accept connection requests from any client program (like Oracle's import utility).  The configuration file for this is: listener.ora, which is also in the \network\admin (or /network/admin in Linux/UNIX) sub-directory of your Oracle_home directory on the server.  The easiest way to configure both of these is with the netca utility.

    Oracle may seem awkward to install and configure compared to SQL Server, but Oracle is not limited to running on just one O/S.

    Author Closing Comment

    The information slightwv provided led me to where the problem was occuring.

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