Public Function ObjektnummerExists(ByVal lngNummer As Long) As Boolean
  Dim SQL As String
  Dim Rs As Recordset
 
  SQL = "SELECT Objektnummer FROM DeineTabelle WHERE Objektnummer = " & CStr( _
    lngNummer)
  Set Rs = Db.OpenRecordset(SQL, dbOpenSnapshot, dbOpenForwardOnly)
  ObjektnummerExists = (Rs.RecordCount <> 0)
  Rs.Close
  Set Rs = Nothing
End Function