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Q181480: FIX: MFC ODBC Cannot Update Access Date/Time with No Date

Article: Q181480
Product(s): Microsoft C Compiler
Version(s): 2.5,2000,5.0,6.0,97
Operating System(s): 
Keyword(s): kbJET kbMFC kbODBC kbVC500 kbVC600 kbGrpDSVCDB kbGrpDSMDAC kbDSupport MSGRAPH kbMDAC250
Last Modified: 17-JUL-2001

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The information in this article applies to:

- The Microsoft Foundation Classes (MFC), used with:
   - Microsoft Visual C++, 32-bit Enterprise Edition, version 5.0 
   - Microsoft Visual C++, 32-bit Professional Edition, version 5.0 
   - Microsoft Visual C++, 32-bit Enterprise Edition, version 6.0 
   - Microsoft Visual C++, 32-bit Professional Edition, version 6.0 
   - Microsoft Visual C++, 32-bit Learning Edition, version 6.0 
   - Microsoft Access 2000 
- Microsoft Data Access Components version 2.5 
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SYMPTOMS
========

When you update records in an Access database using the ODBC cursor library and
you previously added a date/time field in Access without a date using the
CRecordset (with TIMESTAMP_STRUCT) classes, MFC throws the following exception:

  No Rows Affected

CAUSE
=====

The ODBC WHERE clause fails to find the record it needs to update it.

RESOLUTION
==========

This problem has been fixed in MDAC 2.6. For MDAC versions before 2.6 use the
following workarounds:

You must always enter a date in the Access date/time field for CRecordset classes
using the ODBC cursor library.

You can also resolve this problem by switching to dynasets.

STATUS
======



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

If you have to use the ODBC cursor library, you must always enter a date along
with a time in the Access date/time field. If you only enter a time, the
recordset will fail to post updates and the MFC exception "No Rows Affected"
will be thrown. This occurs because the ODBC cursor library attempts to update
the database using an UPDATE clause and attempts to select all columns to ensure
a unique record. During this selection, the date field fails to be resolved.

If you do not have to use the ODBC cursor library, you can open the recordset as
a dynaset, which effectively eliminates this problem.

REFERENCES
==========

Visual C++, Microsoft Foundation Class Reference, Class Library Reference:
Crecordset; CDatabase


Additional query words: MfcDatabase

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Keywords          : kbJET kbMFC kbODBC kbVC500 kbVC600 kbGrpDSVCDB kbGrpDSMDAC kbDSupport MSGRAPH kbMDAC250 kbMDAC260fix kbMDACNoSweep 
Technology        : kbAudDeveloper kbMFC
Version           : :2.5,2000,5.0,6.0,97
Issue type        : kbbug
Solution Type     : kbfix

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