I have oracle11g2 installed on my noteobook.

I then installed the Oracle Database 11g XE. Now a .dll which uses the oracle11g2 client does not work anymore. First I recogniced that I had now two tnsnames.ora, which I resolved by linking the new one to the old one. But still my program cannot connect via the dll and throws an error.

I am relatively sure that the installation broke something which worked before so I need to know which steps the Oracle 11g XE installation procedure performs to system variable (like PATH) or to registry entries which might be important? Is there something like an installation log or can I somehow revert all changes which were done during installation?

My system is running Windows 7 x64.

Best regards, Fox

1 Answer 1


XE changes the following:

  • tnsnames.ora
  • Path variables
  • takes the default port 1521 for itself and this cannot be changed

The best way to install XE and other products is to install XE first, then any other Oracle version afterwards.

I think you can fix this by

  • examining the path variables by entering PATH at the command line
  • ensuring that each installation has a file path to the bin folder, something like this

    c:\oracle\db11g\product\11.1.0\db_1\bin; c:\XE\product\11.1.0\db_1\bin;

  • check that the listener.ora has the correct parameters by starting a command line and entering lsnrctl status This will show you which listener is in use, it's location and what databases it is servicing.

  • change the port for the non XE database to anything other than 1521 in the listener.ora
  • If I just uninstall XE and have the correct PATH and the correct tnsnames.ora (tested via tnsping.exe - it findes the defined databases) it should work? Because if XE is uninstalled I don't have a listener anymore?
    – JoeFox
    Jun 30, 2015 at 4:02
  • Every Oracle database that connects outside a machine is listed in a listener. I don't have access to my test box so I can't tell you whether you have two listeners, one for each install, or one that lists both
    – kevinskio
    Jun 30, 2015 at 9:59
  • If I only want to use the client features of oracle from the oracle11g installation. Then dba.stackexchange.com/questions/65597/… suggests, that I do not need lsnrctl. In fact it is missing in my installation. I have completely deinstalled all my oracle products and reinstalled my oracle11g with Oracle Universall Installer.
    – JoeFox
    Jul 1, 2015 at 5:32
  • Yes, you don't need a listener for a client installation. It was not clear from your question where you say you installed two Oracle databases that you only wanted a client install
    – kevinskio
    Jul 1, 2015 at 12:33

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