Article: Q182954
Product(s): Microsoft Visual Basic for Windows
Version(s):
Operating System(s):
Keyword(s): kbGrpDSVBDB
Last Modified: 09-JAN-2000
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The information in this article applies to:
- Microsoft Visual Basic Enterprise Edition for Windows, versions 5.0, 6.0
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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
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Keywords : kbGrpDSVBDB
Technology : kbVBSearch kbAudDeveloper kbZNotKeyword6 kbZNotKeyword2 kbVB500Search kbVB600Search kbVB500 kbVB600
Issue type : kbprb
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