BUG: RFX_DATE() May Use Incorrect Precision Value

• The Microsoft Foundation Classes (MFC), included 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

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
Version : 1.5,1.51,2.0,2.1,4.0,4.1,4.2,5.0,6.0
Platform : NT WINDOWS
Issue type : kbbug