DOCUMENT:Q159956  04-AUG-2001  [visualc]
TITLE   :FIX: Dirty Flag Not Cleared During Edit() or Update()
PRODUCT :Microsoft C Compiler
PROD/VER:4.2 4.2b
OPER/SYS:
KEYWORDS:kbDatabase kbMFC kbODBC kbVC kbVC500fix

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The information in this article applies to:

 - The Microsoft Foundation Classes (MFC), included with:
    - Microsoft Visual C++, 32-bit Enterprise Edition, version 4.2 
    - Microsoft Visual C++, 32-bit Professional Edition, version 4.2 
    - Microsoft Visual C++, 32-bit Enterprise Edition, version 4.2b 
    - Microsoft Visual C++, 32-bit Professional Edition, version 4.2b 
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SYMPTOMS
========

When you use the Microsoft Foundation Classes (MFC) ODBC to update a record that
has not been modified since the last call to CRecordset::Update(), the fields
within the record show up as dirty.

CAUSE
=====

Neither the CRecordset::Edit() function nor the CRecordset::Update() function
clear the dirty flag.

RESOLUTION
==========

Override CRecordset::Update() and clear the dirty flags for your recordset after
calling the base class CRecordset::Update().

STATUS
======

Microsoft has confirmed this to be a bug in the Microsoft products listed at the
beginning of this article. This bug has been fixed in Visual C++ version 5.0.

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

The following sample code displays the problem. The second sample shows how to
implement the workaround:

Sample Code 1
-------------

      // m_pSet is a pointer to a CRecordset derived class, called CMySet,
      // that has a text member variable called m_Name.

      m_pSet->Edit();
      m_pSet->m_Name = "NewName";
      m_pSet->Update();

      m_pSet->Edit();
      if( m_pSet->IsFieldDirty( &(m_pSet->m_Name) ) )
          TRACE( "Name is dirty\n" );
      // The next call will update the record, even though the data has
      // not changed.
      m_pSet->Update();

Sample Code 2
-------------

      // Override CRecordset::Update and clear the dirty flags:
      BOOL CMySet::Update()
      {
         BOOL bReturn = CRecordset::Update();
         if (m_bCheckCacheForDirtyFields &&
            !(m_dwOptions & optimizeBulkAdd))
         {
            SetFieldDirty(NULL, FALSE);
         }
         return bReturn;
      }

Additional query words: kbVC420bug kbDSupport

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Keywords          : kbDatabase kbMFC kbODBC kbVC kbVC500fix 
Technology        : kbAudDeveloper kbMFC
Version           : 4.2 4.2b
Issue type        : kbbug
Solution Type     : kbfix

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