DAO error 3028 may occur when you try to create a workspace DAO object in Visual C++

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This article was previously published under Q146876

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SYMPTOMS

The following DAO error 3028 may occur when you try to create a workspace DAO object:

Can't start application. The system database is missing or opened
exclusively by another user.

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CAUSE

This error can occur if you have failed to specify a system database or have assigned the system database after performing operations with the database engine.

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It is important that the SystemDB property of the database engine be set prior to performing any operations with the database engine. If you are using the dbDAO C++ classes included with the DAO SDK, you can set the system database by using code similar to this code:

   // get database engine object but don't fill its collections
   CdbDBEngine eng(FALSE, FALSE);

   // set the system database
   eng.SetSystemDB(_T("d:\\work\\sectest.mdw"));

   // Finish initializing the engine object
   eng.Start();

   CdbWorkspace wsp;

   // The following function call will generate the 3028
   // error if a System Database hasn't been assigned or if the
   // second argument of the constructor for CdbDBEngine didn't
   // receive FALSE.

   wsp= eng.CreateWorkspace(_T("Test"),_T("MyUserName"),
                            _T("MyPassword"));

Or, alternately, use the CdbDBEngine::SetInitPath() method before opening or creating a CdbWorkspace object.

If you are using the MFC DAO classes, use code similar to this code:

   //Initialize global MFC DAO engine
   AfxDaoInit( );
   DAODBEngine* pDBEngine = AfxDaoGetEngine( );

   // Set up system database
   COleVariant var( _T("d:\\work\\sectest.mdw"), VT_BSTRT );
   // NOTE: put_SystemDB was a late addition to DAO
   // and is not yet wrapped by MFC
   DAO_CHECK( pDBEngine->put_SystemDB( var.bstrVal ) );

   CDaoWorkspace wsp;
   wsp.Create(_T("Test"),_T("MyUserName"), _T("MyPassword"));

Or, alternately, use the CDaoWorkspace::SetInitPath() method before opening or creating a CDaoWorkspace object.

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