MDE Property [Access 2003 VBA Language Reference]
You can use the MDE property to determine whether a database has been saved as an .mde file.
Note This property is only available with a Microsoft Access database (.mdb).
When a database is saved as an .mde file, Microsoft Access adds the MDE property to the database and sets it to the String value "T".
The MDE property can be determined only by using Visual Basic and is read-only in all views.
Important Trying to determine the MDE property for a database that hasn't been saved as an .mde file will generate run-time error 3270 (property not found). The MDE property doesn't exist in a database until the database is saved as an .mde file.
You can convert a database to an .mde file by pointing to Database Utilities on the Tools menu and clicking Make MDE File. When you save a database as an .mde file, Microsoft Access removes all editable source code, compiles all modules, and compacts the database. Your Visual Basic code still works, but the code cannot be viewed or changed. In addition, you can't add or make changes to form or report objects.
Warning Be sure to retain a copy of your original database. If you need to change any code or the design of objects in an .mde database, you must do so in the original database and then create a new .mde database. You will also need the original database in order to convert to future versions of Microsoft Access because you can't directly convert .mde files.
Saving a database as an .mde file is most appropriate when you want to prevent changes to forms or reports, or hide your Visual Basic code from the database users. You could also convert a database to an .mde file when you create your own wizards or for the front-end portion of a front-end/back-end application.
A replicated database can't be saved as an .mde file; however, once a database is saved as an .mde file, it can be replicated.
The following example uses the IsItMDE function to check the MDE property for the current database:
Dim dbs As Object Set dbs = CurrentDb If IsItMDE(dbs) <> True Then ' Process custom database code. End If Function IsItMDE(dbs as Object) As Boolean Dim strMDE As String On Error Resume Next strMDE = dbs.Properties("MDE") If Err = 0 AND strMDE = "T" Then ' This is an MDE database. IsItMDE = True Else IsITMDE = False End if End Function