BUG: Reverting to OLDVAL() Causes Error with Table Buffering

• Microsoft Visual FoxPro for Windows, versions 5.0, 5.0a

SYMPTOMS

With Table Buffering activated, trying to replace the current value with the value assigned to the OLDVAL() function causes an error, and the table is not updated.

STATUS

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

MORE INFORMATION

Steps to Reproduce Behavior

1. Create and Populate a table as follows:

         CREATE TABLE sample ( Field1 C(5) UNIQUE )
         INSERT INTO sample ( Field1 ) VALUES ( "one  " )
         INSERT INTO sample ( Field1 ) VALUES ( "two  " )
         INSERT INTO sample ( Field1 ) VALUES ( "three" )
   

2. Set optimistic(5) or pessimistic(4) table buffering on the table as follows:

         SET MULTILOCK ON
         =CURSORSETPROP( "Buffering", 5 )
   

3. Change Field1 of the first record as follows:

         GO Top
         REPLACE field1 WITH "four"
   

4. Now move the record pointer to confirm the change as follows:

         SKIP
         SKIP -1
   

5. Insert OLDVAL() into the record's field, which was just changed, and move the record pointer to submit the change as follows:

         REPLACE field1 WITH OLDVAL( "Field1" )
         SKIP
   

In order to Update the table again or to close it, you have to Revert the table (TableRevert(.T.)), which updates the table back to before the updates in steps 3 through 5 above.