MDAC 2.5 SDK - ADO

IsolationLevel and Mode Properties Example (VB)

See Also

This example uses the Mode property to open an exclusive connection, and the IsolationLevel property to open a transaction that is conducted in isolation of other transactions.

Public Sub IsolationLevelX()

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

   ' Assign connection string to variable.
   strCnn = "Provider=sqloledb;" & _
      "Data Source=srv;Initial Catalog=Pubs;User Id=sa;Password=; "

   ' Open connection and Titles table.
   Set cnn1 = New ADODB.Connection
   cnn1.Mode = adModeShareExclusive
   cnn1.IsolationLevel = adXactIsolated
   cnn1.Open strCnn
   
   Set rstTitles = New ADODB.Recordset
   rstTitles.CursorType = adOpenDynamic
   rstTitles.LockType = adLockPessimistic
   rstTitles.Open "Titles", cnn1, , , adCmdTable
   
   cnn1.BeginTrans

   ' Display connection mode.
   If cnn1.Mode = adModeShareExclusive Then
      MsgBox "Connection mode is exclusive."
   Else
      MsgBox "Connection mode is not exclusive."
   End If

   ' Display isolation level.
   If cnn1.IsolationLevel = adXactIsolated Then
      MsgBox "Transaction is isolated."
   Else
      MsgBox "Transaction is not isolated."
   End If

   ' Change the type of psychology titles.
   Do Until rstTitles.EOF
      If Trim(rstTitles!Type) = "psychology" Then
         rstTitles!Type = "self_help"
         rstTitles.Update
      End If
      rstTitles.MoveNext
   Loop

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

   ' Restore original data.
   cnn1.RollbackTrans
   rstTitles.Close
   
   cnn1.Close

End Sub