PRB: Bookmarks are not Persisted or Marshalled

• ActiveX Data Objects (ADO), versions 1.5, 2.0
• Microsoft Visual Basic Enterprise Edition for Windows, version 6.0

SYMPTOMS

After a recordset has been reopened, once persisted to disk or marshalled across processes or computer boundaries, the bookmarks are no longer correct and they appear to be reset.

CAUSE

Bookmarks are not preserved when a recordset is persisted to a file with the Save method or when marshalled across processes or computer boundaries.

STATUS

This behavior is by design.

MORE INFORMATION

NOTE: this sample code was written for ADO 2.0. ADO 1.5 does not support a Save method.

Steps to Reproduce Behavior

1. Start Visual Basic.



2. Add a project reference to the Microsoft ActiveX Data Objects Library.



3. Paste the following code in the default forms Load method:

   
         Set oRs = New ADODB.Recordset
   
         With oRs
          .CursorLocation = adUseClient
          .CursorType = adOpenStatic
          .LockType = adLockBatchOptimistic
          .Fields.Append "c_col1", adChar, 2
          .Fields.Append "c_col2", adChar, 2
          .Open
         End With
   
         oRs.AddNew
         oRs(0) = "1"
         oRs.Update
         oRs.AddNew
         oRs(0) = "2"
         oRs.Update
         oRs.AddNew
         oRs(0) = "3"
         oRs.Update
         oRs.MoveFirst
   
         Debug.Print oRs.RecordCount
         Debug.Print oRs.Bookmark
   
         'Delete the first row, move to the new first row, and check its book
         'mark value.
         oRs.Delete
         oRs.MoveFirst
         Debug.Print oRs.Bookmark
   
         'The Save method can not overwrite existing files.
         On Error Resume Next
         Kill "C:\mytmp.txt"
         On Error GoTo 0
   
         oRs.Save "C:\mytmp.txt"
         oRs.Close
         Set oRs = Nothing
   
         'Re-open persisted file and check the first row's bookmark.
         'Prior to persisting the recordset the first row's bookmark was a 2.
   
         Set oRs = New ADODB.Recordset
         oRs.Source = "C:\mytmp.txt"
         oRs.Open
         oRs.MoveFirst
         Debug.Print oRs.Bookmark
         Debug.Print oRs.RecordCount
         Debug.Print oRs(0)
   
         Unload Me 




4. From the View menu, choose Immediate Window.



5. Press F8 repeatedly to step through the code.

REFERENCES

For additional information about ADO Recordset Properties, please see the following article(s) in the Microsoft Knowledge Base:

Q185423 Most ADO Recordset Properties are not Marshalled

Additional query words:

Keywords          : kbADO kbADO150 kbADO200 kbDatabase kbSweepNext 
Version           : WINDOWS:1.5,2.0,6.0
Platform          : WINDOWS 
Issue type        : kbprb 

Last Reviewed: May 27, 1999