How To Create an .MDB File for Microsoft Access Databases

MORE INFORMATION

You can use a user-defined resource to attach miscellaneous data to a .EXE file. If an .mdb file is made into a resource, the resource can be loaded at run time and then written to an .mdb file. The steps required to do this are as follows:

1. Create an .mdb file either by using Microsoft Access or MSQuery.
2. Create the .mdb file as a user-defined resource by adding the following line to your .RC file:

         mdb_file  MDB_RESOURCE filename.mdb
   						

   where:

         mdb_file      is  a name for identifying the resource.
         MDB_RESOURCE  is  a name for identifying the type of the resource
                           and can be any user-defined type.
         filename.mdb  is  the name of the .mdb file.
   						

3. Load the resource and write it out to an .mdb file. You can use the following function, from anywhere in your application, to create the .mdb file. (A typical place for creating the .mdb file would be the override of the CWinApp::InitInstance() function.)

      CreateMDBFile()
      {
         // Get the instance handle - required for loading the resource
         HINSTANCE hInst = AfxGetInstanceHandle();
   
         // Load the user-defined resource.
         HRSRC hmdbFile = ::FindResource(hInst, "mdb_file", "MDB_RESOURCE");
            HGLOBAL hRes = ::LoadResource(hInst, hmdbFile);
            DWORD dwResSize = ::SizeofResource(hInst, hmdbFile);
   
            if (hRes != NULL)
            {
               UINT FAR* lpnRes = (UINT FAR*)::LockResource(hRes);
               CString szFileName = "Filename.mdb";
   
               TRY
               {
                  // Create the .mdb file
                  CFile f( szFileName, CFile::modeCreate | CFile::modeWrite );
   
                  // Write the user-defined resource to the .mdb file
                  f.WriteHuge(lpnRes, dwResSize);
                  f.Flush();
               }
               CATCH( CFileException, e )
               {
         #ifdef _DEBUG
                afxDump << "File could not be opened " << e->m_cause << "\n";
         #endif
               }
               END_CATCH
   
         #ifndef WIN32 //Unlock Resource is obsolete in the Win32 API
               ::UnlockResource(hRes);
         #endif
               ::FreeResource(hRes);
            }
         }
   						

The one disadvantage of this method is that it increases the size of the .exe file according to the size of the .mdb file. Because even an empty .mdb file is 64K in size, the .exe is increased by at least 64K. One way to reduce the size of the .exe is to store a compressed .mdb file onto the .exe and expand it at run time when storing the resource.