DOCUMENT:Q126134  25-JUL-2001  [visualc]
TITLE   :FIX: Date/Time Fields Fail to Update When Using a Dynaset
PRODUCT :Microsoft C Compiler
PROD/VER:2.00
OPER/SYS:
KEYWORDS:kbDatabase kbMFC kbODBC kbVCkbbuglist kbfixlist

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

 - The Microsoft Foundation Classes (MFC), included with:
    - Microsoft Visual C++, 32-bit Editions, version 2.0 
-------------------------------------------------------------------------------

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:

1. 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 );

2. 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);
      }

3. 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          : kbDatabase kbMFC kbODBC kbVC kbbuglist kbfixlist
Technology        : kbAudDeveloper kbMFC
Version           : 2.00
Issue type        : kbbug
Solution Type     : kbfix

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