MDAC 2.5 SDK - ADO

BeginTrans, CommitTrans, and RollbackTrans Methods Example (VB)

See Also

This example changes the book type of all psychology books in the Titles table of the database. After the BeginTrans method starts a transaction that isolates all the changes made to the Titles table, the CommitTrans method saves the changes. You can use the RollbackTrans method to undo changes that you saved using the Update method.

Public Sub BeginTransX()

   Dim cnn1 As ADODB.Connection
   Dim rstTitles As ADODB.Recordset
   Dim strCnn As String
   Dim strTitle As String
   Dim strMessage As String

   ' Open connection.
      strCnn = "Provider=sqloledb;" & _
      "Data Source=srv;Initial Catalog=Pubs;User Id=sa;Password=; "
   Set cnn1 = New ADODB.Connection
   cnn1.Open strCnn

   ' Open Titles table.
   Set rstTitles = New ADODB.Recordset
   rstTitles.CursorType = adOpenDynamic
   rstTitles.LockType = adLockPessimistic
   rstTitles.Open "titles", cnn1, , , adCmdTable
   
   rstTitles.MoveFirst
   cnn1.BeginTrans

   ' Loop through recordset and ask user if she wants 
   ' to change the type for a specified title.
   Do Until rstTitles.EOF
      If Trim(rstTitles!Type) = "psychology" Then
         strTitle = rstTitles!Title
         strMessage = "Title: " & strTitle & vbCr & _
         "Change type to self help?"

         ' Change the title for the specified
         ' employee.
         If MsgBox(strMessage, vbYesNo) = vbYes Then
            rstTitles!Type = "self_help"
            rstTitles.Update
         End If
      End If

         rstTitles.MoveNext
   Loop

   ' Ask if the user wants to commit to all the 
   ' changes made above.
   If MsgBox("Save all changes?", vbYesNo) = vbYes Then
      cnn1.CommitTrans
   Else
      cnn1.RollbackTrans
   End If

   ' Print current data in recordset.
   rstTitles.Requery
   rstTitles.MoveFirst
   Do While Not rstTitles.EOF
      Debug.Print rstTitles!Title & " - " & rstTitles!Type
      rstTitles.MoveNext
   Loop

   ' Restore original data because this
   ' is a demonstration.
   rstTitles.MoveFirst
   Do Until rstTitles.EOF
      If Trim(rstTitles!Type) = "self_help" Then
         rstTitles!Type = "psychology"
         rstTitles.Update
      End If
      rstTitles.MoveNext
   Loop

   rstTitles.Close
   cnn1.Close

End Sub