Knowledge Base

FIX: Date/Time Fields Fail to Update When Using a Dynaset

Article ID: 126134

Article Last Modified on 11/21/2006

APPLIES TO

Microsoft Foundation Class Library 4.2, when used with:
- Microsoft Visual C++ 2.0 Professional Edition

This article was previously published under Q126134

SYMPTOMS

An attempt to update a date/time field using a CTime object will fail. The CRecordset::RFX_Date() doesn't work correctly, and the date/time field in the database table isn't changed. This problem occurs only when passing CRecordset::dynaset as the first parameter to the CRecordset::Open() member function.

CAUSE

The RFX_Date() function that takes a CTime object as a parameter fails to transfer the CTime data to its TIMESTAMP_STRUCT proxy before performing an update.

RESOLUTION

To work around this problem, follow these steps:

In one of the header files, such as the CRecordset's header file, create the following function prototype:

   void RFX_Date2( CFieldExchange* pFX, const char* szName, CTime& value );

In the CRecordset's .CPP file or elsewhere, add this RFX_Date2() definition:

   void RFX_Date2(CFieldExchange* pFX, const char *szName,
      CTime& value)
   {
    ASSERT(AfxIsValidAddress(pFX, sizeof(CFieldExchange)));

    if (pFX->m_nOperation==CFieldExchange::BindFieldForUpdate)
    {
            if(pFX->m_nFieldType == CFieldExchange::param)
                return;

            //pFX-m_nFields hasn't been incremented yet so no need to
            // subtract 1 for indexing m_pvFieldProxy
            if (pFX->m_prs->m_pvFieldProxy[pFX->m_nFields] != NULL)
            {
                // Fill buffer (expected by SQLSetPos) with new field data
                TIMESTAMP_STRUCT* pts;
                pts = (TIMESTAMP_STRUCT*)
                   pFX->m_prs->m_pvFieldProxy[pFX->m_nFields];
                pts->year = (SWORD)value.GetYear();
                pts->month = (UWORD)value.GetMonth();
                pts->day = (UWORD)value.GetDay();
                pts->hour = (UWORD)value.GetHour();
                pts->minute = (UWORD)value.GetMinute();
                pts->second = (UWORD)value.GetSecond();
                pts->fraction = 0;
            }
       }
       RFX_Date(pFX, szName, value);
   }

Modify the DoFieldExchange member function of the CRecordset class, replacing calls to RFX_Date with calls to the RFX_Date2 function described above.

STATUS

Microsoft has confirmed this to be a bug in the Microsoft products listed at the beginning of this article. This problem was corrected in Microsoft Visual C++ version 2.1.

MORE INFORMATION

MFC Technote #43 contains more information about record field exchange (RFX) functions and CFieldExchange operations.

Additional query words: 2.00 3.00

Keywords: kbbug kbdatabase kbfix KB126134

Microsoft KB Archive/126134

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