Q122218: BUG: RFX_DATE() May Use Incorrect Precision Value

Article: Q122218
Product(s): Microsoft C Compiler
Version(s): 1.5,1.51,2.0,2.1,4.0,4.1,4.2,4.2b,5.0,6.0
Operating System(s): 
Keyword(s): kbVC600bugkbbuglist
Last Modified: 11-FEB-2002

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

- The Microsoft Foundation Classes (MFC), used with:
   - Microsoft Visual C++ for Windows, 16-bit edition, versions 1.5, 1.51 
   - Microsoft Visual C++, 32-bit Editions, versions 2.0, 2.1, 4.0, 4.1, 4.2, 4.2b, 5.0, 6.0 
   - Microsoft Visual C++.NET (2002) 
-------------------------------------------------------------------------------

SYMPTOMS
========

Using the RFX_Date() functions in the Microsoft Foundation Classes fails to work
with date/time fields with some ODBC drivers. A general ODBC error or 'invalid
precision' error may occur depending upon the ODBC driver.

CAUSE
=====

RFX_Date() calls SQLSetParam() and SQLBindCol() with a precision parameter equal
to 23 (sizeof TIMESTAMP_STRUCT). Some ODBC drivers may not use the same
precision for a SQL_TIMESTAMP. For example, some ODBC drivers may choose ignore
seconds or fractions of a second; in these cases, the precision may be smaller.

RESOLUTION
==========

To work around this problem, you must re-write the RFX_Date() function and call
your new function in your CRecordset's DoFieldExchange(), replacing the
RFX_Date() call.

In your new RFX_Date() function you will need to:

1. Get the precision of a SQL_TIMESTAMP column by using the ODBC function
  SQLGetTypeInfo() for the data source connected to by the CRecordset.

2. Store the precision value in a variable in your recordset so that you can
  retrieve it later.

3. Replace all references of TIMESTAMP_PRECISION in your RFX_Date() function
  with a reference to the precision variable contained in your CRecordset
  class.

STATUS
======

Microsoft has confirmed this to be a bug in the Microsoft products listed at the
beginning of this article. We are researching this bug and will post new
information here in the Microsoft Knowledge Base as it becomes available.

Additional query words: kbVC150bug kbVC151bug kbVC200bug kbVC210bug kbVC400bug kbVC410bug kbVC420bug kbVC500bug kbVC600bug kbmfc kbdatabase kbodbc kb3rdparty

======================================================================
Keywords          : kbVC600bug kbbuglist
Technology        : kbAudDeveloper kbMFC
Version           : :1.5,1.51,2.0,2.1,4.0,4.1,4.2,4.2b,5.0,6.0
Issue type        : kbbug

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

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 1986-2002.