FIX: ADO Suppresses Errors When Fetching into Nonvariant Datatypes

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Article ID: 274423 - View products that this article applies to.
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SYMPTOMS

When fetching rowset values into nonvariant datatypes, ActiveX Data Objects (ADO) may suppress errors that are related to the status of the recordset, such as notifications that the record is locked by another user.

This problem occurs in Microsoft Data Access Components (MDAC) version 2.50.4403.12 (Microsoft Windows 2000/MDAC 2.5 RTM) and 2.51.5303.5 (Windows 2000/MDAC 2.5 SP1). This problem does not occur in MDAC version 2.60.6526.3 (MDAC 2.6 RTM).

CAUSE

A slightly different code path is taken depending on whether the application is fetching into variant datatypes. The use of variants is wrapped in an internal context object which has the ability to return error information. Nonvariants do not have this context wrapper and do not return error information.

RESOLUTION

To resolve this problem, obtain the latest service pack for Microsoft Data Access Components 2.5. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:
293312 INFO: How to Obtain the Latest MDAC 2.5 Service Pack
The English version of this has the file attributes (or later) that are listed in the following table. The dates and times for these files are listed in coordinated universal time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time tool in Control Panel.
   Date       Version        Size             File name
   ----------------------------------------------------------
   8/29/2000  2.51.5629.0     20,480 bytes    Msader15.dll
   8/29/2000  2.51.5629.0    487,696 bytes    Msado15.dll
   8/29/2000  2.51.5629.0    172,304 bytes    Msadomd.dll
   8/29/2000  2.51.5629.0     57,616 bytes    Msador15.dll
   8/29/2000  2.51.5629.0    184,592 bytes    Msadox.dll
   8/29/2000  2.51.5629.0     57,616 bytes    Msadrh15.dll
   8/29/2000  2.51.5629.0     94,480 bytes    Msjro.dll
				

WORKAROUND

There is no workaround for this issue.

STATUS

Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article. This problem was first corrected in Microsoft Data Access Components 2.5 Service Pack 2.

MORE INFORMATION

Steps to Reproduce Behavior

  1. Copy the following code into a Visual Basic project:

    Note You must change the UID <username> value and the PWD =<strong password> value to the correct values before you run this code. Make sure that UID has the appropriate permissions to perform this operation on the database.
    Dim cn As ADODB.Connection, cnOtherUser As ADODB.Connection
    Dim rs As ADODB.Recordset, rsOtherUser As ADODB.Recordset
    Dim strConn As String, strSQL As String
    Dim varData As Variant, intData As Integer
    
    strConn = "Provider=MSDASQL;Driver={SQL Server};Server=YourServer;Database=Northwind;UID=<user name>;PWD=<strong password>;"
    strSQL = "SELECT * FROM Customers"
    
    Set cnOtherUser = New ADODB.Connection
    cnOtherUser.Open strConn
    Set rsOtherUser = New ADODB.Recordset
    rsOtherUser.Open strSQL, cnOtherUser, adOpenKeyset, adLockPessimistic, adCmdText
    rsOtherUser.MoveFirst
    
    Set cn = New ADODB.Connection
    cn.Open strConn
    cn.CommandTimeout = 10
    Set rs = New ADODB.Recordset
    rs.Open strSQL, cn, adOpenKeyset, adLockPessimistic, adCmdText
    If MsgBox("Use Variant?", vbYesNo) = vbYes Then
        On Error Resume Next
        varData = rs(0)
        If Err.Number <> 0 Then
            MsgBox Err.Description
            Err.Clear
            cn.Errors.Clear
        Else
            MsgBox "No error!"
        End If
        On Error GoTo 0
    Else
        On Error Resume Next
        intData = rs(0)
        If Err.Number <> 0 Then
            MsgBox Err.Description
            Err.Clear
            cn.Errors.Clear
        Else
            MsgBox "No error!"
        End If
        On Error GoTo 0
    End If
    rs.Close
    cn.Close
    
    rsOtherUser.Close
    cnOtherUser.Close
    					
  2. Add a reference to the Microsoft ActiveX Data Objects 2.5 Library.
  3. Run the code, and choose Yes when prompted to use a Variant. Note that a "Timeout expired" error message is returned, indicating that the records could not be fetched in the specified amount of time.
  4. Run the code again, and this time choose No when prompted to use a Variant. This time an error is returned stating that there is no current record, but there is no indication that you exceeded your timeout.

REFERENCES

For additional information, click the article numbers below to view the articles in the Microsoft Knowledge Base:
247757 FIX: Connection Leak Using Parameterized Command In ADO
264442 FIX: ADO Recordset Loses Filter Property When Marshalled In-Proc
264701 FIX: Passing ADO Recordset ByRef Resets Error Information

Properties

Article ID: 274423 - Last Review: February 28, 2014 - Revision: 2.2
APPLIES TO
  • Microsoft ActiveX Data Objects 2.5
  • Microsoft Data Access Components 2.5
  • Microsoft Data Access Components 2.5 Service Pack 1
Keywords: 
kbnosurvey kbarchive kbhotfixserver kbqfe kbado250fix kbbug kbfix kbmdac250fix kbqfe KB274423

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