Selecting a different Db2 copy for your Windows CLI application

By default, CLI applications running on Windows systems make use of the default Db2 copy. However, applications can use any Db2 copy that is installed on the system.

Before you begin

Ensure your Windows CLI environment is set up.


Restrictions

See Multiple Db2 copies on the same computer (Windows) and IBM data server client connectivity using multiple copies.

Procedure

The following methods allow CLI applications to successfully access a different Db2 copy on Windows operating systems:

  • Using the Db2 command window from the Start > Programs > IBM Db2 Copy Name > Command Line Tools > Db2Command Window: the command window is already set up with the correct environment variables for the particular Db2 copy chosen.
  • Using db2envar.bat from a command window:
    1. Open a command window.
    2. Run the db2envar.bat file using the fully qualified path for the Db2 copy that you want the application to use: 
      Db2_Copy_install_dir\bin\db2envar.bat
    3. Run the CLI application from the same command window.

    This will set up all the environment variables for the selected Db2 copy in the command window where the db2envar.bat was run. Once the command window has been closed and a new one opened, the CLI application will run against the default Db2 Copy unless the db2envar.bat for another Db2 copy is run again.

  • Using the db2SelectDB2Copy API: For applications that are dynamically linked, you can call this API before loading any Db2 DLLs within your application process. This API sets up the required environment for your application to use the Db2 copy that you want to use. The /delayload linking option can be used to delay the loading of any Db2 DLL. For example, if your CLI application links db2api.lib, then you must use the /delayload option of your linker to delay the load db2app.dll: 
    cl -Zi -MDd -Tp App.C /link /DELAY:nobind /DELAYLOAD:db2app.dll 
   advapi32.lib psapi.lib db2api.lib delayimp.lib

    To use the API, you will need to include db2ApiInstall.h, which will force your application to statically link in db2ApiInstall.lib.

  • Using LoadLibraryEx: Instead of using LoadLibrary, you can call LoadLibraryEx with the LOAD_WITH_ALTERED_SEARCH_PATH parameter to load the db2app.dll that corresponds to the version of the Db2 copy you want to use. For example: 
    HMODULE hLib = LoadLibraryEx("c:\\sqllib\\bin\\db2app.dll", 
   NULL, LOAD_WITH_ALTERED_SEARCH_PATH);