Microsoft KB Archive/188857

= PRB: Use Open Method to Change CursorType and LockType =

Article ID: 188857

Article Last Modified on 3/2/2005

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APPLIES TO


 * Microsoft ActiveX Data Objects 2.0
 * Microsoft ActiveX Data Objects 2.1
 * Microsoft ActiveX Data Objects 2.5
 * Microsoft ActiveX Data Objects 2.6
 * Microsoft ActiveX Data Objects 2.7

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This article was previously published under Q188857



SYMPTOMS
If a recordset is opened through a connection object or a command object, the CursorType defaults to adOpenForwardOnly, and the LockType defaults to adLockReadOnly if the cursorlocation is adUseServer. Changing these properties before creating the recordset does not cause an error, but the properties are not preserved.



CAUSE
When execute is used to open a recordset, it is creating a recordset with default properties.



RESOLUTION
Use the open method to create the recordset. The preceding properties of the recordset may then be set before the open statement or they may be set with the open statement.



STATUS
This behavior is by design.



MORE INFORMATION
The default CursorLocation is adUseServer, and the default LockType is adLockReadOnly. The default CursorType for adUseServer is adOpenForwardOnly.

The CursorLocation can be set on the connection prior to opening the recordset. This CursorLocation is applied to the recordset opened on this connection. If the connection's CursorLocation is set to adUseClient, the resulting recordset CursorLocation would be adUseClient. The CursorType for adUseClient is always adOpenStatic. The default LockType remains adLockReadOnly.

The following sample code connects to SQL server's Pubs database. The ConnectionString arguments need to be changed to match your setup.

Steps to Reproduce Behavior
 Create a Standard EXE project and select Microsoft Active Data Objects Library (on the Project menu, click References). Place seven command buttons on Form1.  Paste the following code in the Form1 code window: Option Explicit Dim cn As New ADODB.Connection Dim cmd As New ADODB.Command Dim rs As New ADODB.Recordset

Private Sub Command1_Click With cn     .CursorLocation = adUseServer .ConnectionString = "dsn=yourdatasourcename"uid=yourUserId;pwd=yourPassword .Open End With rs.CursorType = adOpenKeyset rs.LockType = adLockOptimistic End Sub

Private Sub Command2_Click Set rs = cn.Execute("select * from authors") End Sub

Private Sub Command3_Click With cmd .ActiveConnection = cn      .CommandType = adCmdText .CommandText = "select * from authors" End With Set rs = cmd.Execute End Sub

Private Sub Command4_Click rs.Open "select * from authors", cn  End Sub

Private Sub Command5_Click Debug.Print "CursorLocation " & rs.CursorLocation; "" Debug.Print "cursortype " & rs.CursorType Debug.Print "locktype " & rs.LockType End Sub

Private Sub Command6_Click If rs.State = 1 Then rs.Close End If    If Not rs Is Nothing Then Set rs = Nothing End If    rs.CursorLocation = adUseServer rs.CursorType = adOpenKeyset rs.LockType = adLockOptimistic End Sub

Private Sub Command7_Click If Not rs Is Nothing Then Set rs = Nothing End If    If cn.State = 1 Then cn.Close End If    If Not cmd Is Nothing Then Set cmd = Nothing End If    If Not cn Is Nothing Then Set cn = Nothing End If    Unload Me   End Sub

Private Sub Form_Load Command1.Caption = "connect" Command2.Caption = "connection.execute" Command3.Caption = "command.execute" Command4.Caption = "open recordset" Command5.Caption = "print recordset attributes" Command6.Caption = "close recordset" Command7.Caption = "quit" End Sub  Run the code, and click Connect. Make sure the Immediate Window is open; if it is not open, select it from the View menu. Click connection.execute; then select the print recordset attributes and close recordset. Note the print out is in the immediate window.</li> Click command.execute, followed by selecting print recordset attributes and close recordset. Note the print out is in the Immediate Window.</li> Click the open recordset followed by selecting print recordset attributes and the close recordset. Again, note the print out in the Immediate Window.</li></ol>

You may test the above sequences for the Connection, Command, and Open methods in any order, and the corresponding print outs will not change for Cursorlocation, Cursortype, and Locktype.

The following table lists the meanings of these numbers: <pre class="fixed_text">       Cursorlocation    Cursortype     Locktype

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0   N/A              adforwardonly   N/A 1   N/A              adopenkeyset    readonly 2   aduseserver      adopendynamic   pessimistic 3   aduseclient      adopenstatic    optimistic

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