Edit

Editing Data

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We have explained how use ADO to connect to a data source, execute a command, get the results in a Recordset object, and navigate within the Recordset. This section focuses on the next fundamental ADO operation: editing data.

This section continues to use the sample Recordset introduced in Examining Data, with one important change. The following code is used to open the Recordset:

'BeginEditIntro  
    Dim strSQL As String  
    Dim objRs1 As ADODB.Recordset  
  
    strSQL = "SELECT * FROM Shippers"  
  
    Set objRs1 = New ADODB.Recordset  
  
    objRs1.Open strSQL, GetNewConnection, adOpenStatic, _  
                adLockBatchOptimistic, adCmdText  
  
    ' Disconnect the Recordset from the Connection object.  
    Set objRs1.ActiveConnection = Nothing  
'EndEditIntro

The important change to the code involves setting the CursorLocation property of the Connection object equal to adUseClient in the GetNewConnection function (shown in the next example), which indicates the use of a client cursor. For more information about the differences between client-side and server-side cursors, see Understanding Cursors and Locks.

The CursorLocation property's adUseClient setting moves the location of the cursor from the data source (the SQL Server, in this case) to the location of the client code (the desktop workstation). This setting forces ADO to invoke the Client Cursor Engine for OLE DB on the client in order to create and manage the cursor.

You might also have noticed that the LockType parameter of the Open method changed to adLockBatchOptimistic. This opens the cursor in batch mode. (The provider caches multiple changes and writes them to the underlying data source only when you call the UpdateBatch method.) Changes that were made to the Recordset will not be updated in the database until the UpdateBatch method is called.

Finally, the code in this section uses a modified version of the GetNewConnection function. This version of the function now returns a client-side cursor. The function looks like this:

'BeginNewConnection  
Public Function GetNewConnection() As ADODB.Connection  
    On Error GoTo ErrHandler:  
  
    Dim objConn As New ADODB.Connection  
    Dim strConnStr As String  
  
    strConnStr = "Provider='SQLOLEDB';Initial Catalog='Northwind';" & _  
                 "Data Source='MySqlServer';Integrated Security='SSPI';"  
  
    objConn.ConnectionString = strConnStr  
    objConn.CursorLocation = adUseClient  
    objConn.Open  
  
    Set GetNewConnection = objConn  
  
    Exit Function  
  
ErrHandler:  
    Set objConn = Nothing  
    Set GetNewConnection = Nothing  
  
    If Err <> 0 Then  
        MsgBox Err.Source & "-->" & Err.Description, , "Error"  
    End If  
End Function  
'EndNewConnection

This section contains the following topics.