DOCUMENT:Q129883  02-FEB-2002  [vbwin]
TITLE   :PRB: Dynaset, Snapshot, and Table Objects No Longer Available
PRODUCT :Microsoft Visual Basic for Windows
PROD/VER:4.00
OPER/SYS:
KEYWORDS:

======================================================================
-------------------------------------------------------------------------------
The information in this article applies to:

 - Microsoft Visual Basic Professional Edition, 16-bit, for Windows, version 4.0 
 - Microsoft Visual Basic Professional Edition, 32-bit, for Windows, version 4.0 
 - Microsoft Visual Basic Enterprise Edition, 16-bit, for Windows, version 4.0 
 - Microsoft Visual Basic Enterprise Edition, 32-bit, for Windows, version 4.0 
-------------------------------------------------------------------------------

SYMPTOMS
========

If you try to dimension a Dynaset, Snapshot, or Table object variable and using
DAO 3.0 (Visual Basic version 4.0 data access objects), you will receive this
runtime error:

   User-defined type not defined.

If you replace the Dynaset, Snapshot, or Table object with the Object or
RecordSet type and use methods such as CreateDynaset, CreateSnapshot, or
OpenTable that are tied to the Dynaset, Snapshot, or Table types, you will
receive this error:

   Feature not available.

CAUSE
=====

Visual Basic version 4.0 has replaced the older Dynaset, Snapshot, and Table
objects with a single RecordSet object. This object can take on the attributes
of any of the older three making it much more powerful and flexible.

RESOLUTION
==========

You can resolve this problem one of two ways.

 - Replace references to the older objects, while retaining lines of code such
   as these:

          Dim DB As Database
          Set DB = OpenDatabase("Biblio.mdb")

   For example, instead of this old code:

          Dim DS As Dynaset
          Dim SS As Snapshot
          Dim TB As Table

          Set DB = OpenDatabase("Biblio.mdb")
          Set DS = DB.CreateDynaset("Authors")
          Set SS = DB.CreateSnapshot("Authors")
          Set TB = DB.OpenTable("Authors")

   Use this new code:

          Dim DB As Database
          Dim RS1 As Recordset
          Dim RS2 As Recordset
          Dim RS3 As Recordset

          Set DB = OpenDatabase("Biblio.mdb")
          Set RS1 = DB.OpenRecordset("Authors", dbOpenDynaset)
          Set RS2 = DB.OpenRecordset("Authors", dbOpenSnapshot)
          Set RS3 = DB.OpenRecordset("Authors", dbOpenTable)

-or-

 - Retain the older syntax and change the Data Access Object (DAO) Type Library
   that your program uses. Although Microsoft recommends the first method for
   future compatibility, using the older syntax is useful for compiling code
   written in previous versions of Visual Basic in version 4.0 with a minimal
   number of changes. To change the DAO Type Library:

   1. Choose References from the Tools menu in Visual Basic.

   2. Clear the Microsoft DAO 3.0 Object Library selection.

   3. Select the Microsoft DAO 2.5/3.0 Compatibility Library.

STATUS
======

This behavior is by design.

MORE INFORMATION
================

Steps to Reproduce Behavior
---------------------------

With the Microsoft DAO 3.0 Object Library selected in Tools REFERENCES
----------------------------------------------------------------------

1. Start a new project in Visual Basic. Form1 is created by default.

2. Add a Data Control (Data1) to Form1.

3. Add the following code to the Form1_Click procedure:

      Sub Form1_Click()
         Dim ds As dynaset  'this generates "User-defined type not defined"

         Data1.Databasename = "Biblio.MDB"
         Data1.RecordSource = "Authors"
         Data1.Refresh

         Set ds = Data1.Recordset.CreateDynaset()
         ' If ds is Dim'd as a RecordSet,
         ' this generates "Feature not available"
         ds.Close
         Set ds = Nothing
      End Sub

4. Start the program by choosing Start from the Run menu or by pressing the F5
   key. The 3251 error will be generated on the CreateDynaset line.

Additional query words: 4.00 vb4win vb4all

======================================================================
Keywords          :  
Technology        : kbVBSearch kbAudDeveloper kbVB400Search kbVB400 kbVB16bitSearch
Version           : 4.00
Issue type        : kbprb

=============================================================================

THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS
PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND.  MICROSOFT DISCLAIMS
ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES
OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.  IN NO
EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR
ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL,
CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF
MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE
POSSIBILITY OF SUCH DAMAGES.  SOME STATES DO NOT ALLOW THE EXCLUSION
OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES
SO THE FOREGOING LIMITATION MAY NOT APPLY.

Copyright Microsoft Corporation 2002.