MDE Files

MDE Files

One way of protecting your application from design changes by users is to compile it into an MDE file. This makes forms, reports and modules uneditable. Additionally, as the MDE file cannot be decompiled, like an MDB file, it will run at the same speed, whereas an MDB file will decompile, causing it to run slower. However, this process does have some down sides:

As this is a one way process, due to the compilation of code, always ensure that you keep a copy of the original MDB file in a very safe place. Without this MDB file, you will not be able to make changes to forms/reports/modules, and you will have to start your design from scratch.
Although Access can 'upgrade' your MDB file from, for example Access 97 to Access 2000, it cannot do the same with MDE files. Therefore, to get an Access 97 MDE to work in Access 2000, you will need to take the original Access 97 MDB file, convert it to an Access 2000 MDB file, and then create an Access 2000 MDE file.
Be aware that there is no way to fix broken references in an MDE file. If the application suffers from a broken reference, you will need to resolve the problem, and then recompile the fixed MDB into an MDE file.

You can check using VBA code if a database is an MDE file by checking the MDE property of the database (note that merely checking the extension is not reliable):

Function fIsMDE() As Boolean
'   Function to check if a database is an MDE file or not
'   Returns:
'       True if the file is an MDE file
'       False if it is not an MDE file
    On Error GoTo E_Handle
    If DBEngine(0)(0).Properties("MDE") = "T" Then fIsMDE = True
fExit:
    Exit Function
E_Handle:
    Select Case Err.Number
        Case 3270 ' Property does not exist - therefore not an MDE file
        Case Else
            MsgBox Err.Description, vbOKOnly + vbCritical, "Error: " & Err.Number
    End Select
    Resume fExit
End Function

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Last modified at 06/06/2006 14:54:30