ACC2000: How to Create an Audit Trail of Record Changes in a Form

• Microsoft Access 2000

SUMMARY

This article shows you how to create a procedure in Visual Basic for Applications that will keep an audit trail of the changes that are made to a record in a form.

MORE INFORMATION

Microsoft provides programming examples for illustration only, without warranty either expressed or implied, including, but not limited to, the implied warranties of merchantability and/or fitness for a particular purpose. This article assumes that you are familiar with the programming language being demonstrated and the tools used to create and debug procedures. Microsoft support professionals can help explain the functionality of a particular procedure, but they will not modify these examples to provide added functionality or construct procedures to meet your specific needs. If you have limited programming experience, you may want to contact a Microsoft Certified Solution Provider or the Microsoft fee-based consulting line at (800) 936-5200. For more information about Microsoft Certified Solution Providers, please see the following page on the World Wide Web:

http://www.microsoft.com/mcsp/

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1. Open the sample database Northwind.mdb.



2. Create a module and type the following line in the Declarations section if it is not already there:




Option Explicit 

3. Type the following procedure:




Function AuditTrail()

Dim MyForm As Form, C As Control
Set MyForm = Screen.ActiveForm
On Err GoTo TryNextC
' Set date and current user if form has been updated.
   MyForm!Updates = MyForm!Updates & Chr(13) & Chr(10) & _
   "Changes made on " & Date & " by " & CurrentUser() & ";"

' If new record, record it in audit trail and exit sub.

If MyForm.NewRecord = True Then
   MyForm!Updates = MyForm!Updates & Chr(13) & Chr(10) & _
      "New Record """
   Exit Function
End If

' Check each data entry control for change and record
    ' old value of Control.

    For Each C In MyForm.Controls

       ' Only check data entry type controls.
       Select Case C.ControlType
          Case acTextBox, acComboBox, acListBox, acOptionGroup
             ' Skip Updates field.
             If C.Name = "Updates" Then GoTo TryNextC

             ' If control was previously Null, record "previous
             ' value was blank."
             If IsNull(C.OldValue) Then
                MyForm!Updates = MyForm!Updates & Chr(13) & _
                   Chr(10) & C.Name & "--previous value was blank"
             ' If control had previous value, record previous value.
             ElseIf C.Value <> C.OldValue Then
                MyForm!Updates = MyForm!Updates & Chr(13) & Chr(10) & _
                   C.Name & "==previous value was " & C.OldValue
          End If
   End Select
   TryNextC:
   Next C
End Function 

4. Save the Module as Module1 and close the Visual Basic Editor.



5. Open the Customers table in Design view and add a new field called Updates. Set the data type of the field to Memo. Close and save the table.



6. Open the Customers form in Design view.



7. In the BeforeUpdate event of the form, type =AuditTrail().



8. If the field list is not displayed, click Field List on the View menu and drag the Updates field from the field list to the form.



9. Open the form in Form view, make a change to the Company Name field of the current record, and press SHIFT+ENTER to save the record.

Additional query words: Tracking Information date time stamp

Keywords : kbdta AccCon KbVBA
Version : WINDOWS:2000
Platform : WINDOWS
Issue type : kbhowto