PRB: rdConcurRowver Availability Incorrect in Books Online

• Microsoft Visual Basic Enterprise Edition for Windows, versions 5.0, 6.0

SYMPTOMS

Books Online indicates that rdConcurRowVer can be used for a table that has only an ID or a timestamp. rdConcurRowVer changes to rdConcurValues when opening a server-side cursor on a table that has only a timestamp or only an ID.

CAUSE

The locktype argument specifies the type of locking used to support concurrency. If a locktype is not supported, it is changed at run-time. rdConcurRowVer locktype is only supported on a data source that has a primary key and a timestamp.

RESOLUTION

If you want to use rdConcurRowVer for a server-side cursor, the table must have a primary key and a timestamp.

STATUS

This behavior is by design.

MORE INFORMATION

Steps to Reproduce Behavior

1. Create a standard exe in Visual Basic. Form1 is created by default. Under Project References, select Microsoft Remote Date Object 2.0.



2. Place two CommandButtons on the form and paste the following code in the form:

   
          Option Explicit
          Dim en As rdoEnvironment
          Dim rs As rdoResultset
          Dim cn As rdoConnection
          Dim sqlstr As String
   
          Private Sub Command1_Click()
             sqlstr = "select * from tablename"
              Set rs = cn.OpenResultset(sqlstr, rdOpenKeyset, _
                 rdConcurRowVer)
          End Sub
   
          Private Sub Command2_Click()
             If Not (rs Is Nothing) Then
                rs.Close
             End If
             cn.Close
             Unload Me
          End Sub
   
          Private Sub Form_Load()
            Set en = rdoEnvironments(0)
            en.CursorDriver = rdUseServer
            Set cn = en.OpenConnection(dsName:="datasourcename", _
              Prompt:=rdDriverNoPrompt, _
              Connect:="uid=sa;pwd=;database=PUBS;")
            Command1.Caption = "resultset"
            Command2.Caption = "quit"
          End Sub 




3. Replace the datasourcename and the table name above.



4. The table name should be changed to different tables, such as primary key and timestamp, to try out the various combinations (just primary key, just timestamp, just id, id and timestamp, and none of the above).



5. Run the form and execute the resultset click button. Pause the execution.



6. Select "add watch" from the debug window. Create a watch for rs.



7. When the watch window appears, click the plus sign (+) and look at locktype. Note that the only time locktype shows rdConcurRowVer is when the table has a timestamp and a primary key.

REFERENCES

"Hitchhikers Guide to Visual Basic & SQLServer" - Fifth Edition pp 430-435 and pp 370-372

Visual Basic 5.0 Enterprise Edition Help files and Books Online under "Choosing an RDO Cursor Type"

Additional query words: kbRDO kbVBp500 kbVBp600 kbdse kbDSupport kbVBp

Keywords : kbGrpVBDB
Version :
Platform : WINDOWS
Issue type : kbprb