BUG: Full Outer Join Does Not Respect Deleted Records

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

SYMPTOMS

The full outer join does not respect deleted records that occur in the second table listed in the SELECT-SQL statement.

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.

MORE INFORMATION

The query result from a full outer join should contain all matching and non- matching rows from both tables. However, deleting records in the second table causes erroneous results to appear.

In the following example, when the parent table, cur1, does not find the deleted records in the second table, cur2, the result set fills with nulls for those records. Then, as it processes the deleted records in cur2 and does not find matches for them, it adds more null records to the result set.

Steps to Reproduce Behavior

1. Create a program called Ztest and add the following code:

   
         CREATE CURSOR cur1 (id_1 I(4), desc_1 C(20))
         CREATE CURSOR cur2 (id_2 I(4), desc_2 C(20))
   
   
         FOR l_n = 1 TO 100
            INSERT INTO cur1 (id_1, desc_1) VALUES (l_n, "TABLE1__"  + ;
            ALLTRIM(STR(l_n)))
            INSERT INTO cur2 (id_2, desc_2) VALUES (l_n, "TABLE2__"  + ;
            ALLTRIM(STR(l_n)))
         ENDFOR
         SET DELETED ON
         SELECT * FROM cur1 FULL OUTER JOIN cur2 ON id_1 = id_2
         WAIT WINDOW STR(_TALLY)+" records returned when no records are
         deleted."
   
         ** Delete the last 50 records in cur1.
         GO 51 IN cur1
         DELETE REST IN cur1
   
         ** Issue the SQL statement again.
         SELECT * FROM cur1 FULL OUTER JOIN cur2 ON id_1 = id_2
         WAIT WINDOW STR(_TALLY)+" records returned when 50 records are
         deleted;
         in cur1"
   
         ** Recall the records in cur1.
         SET DELETED OFF
         RECALL ALL IN cur1
         SET DELETED ON
   
         ** Delete the last 50 records in cur2.
         GO 51 IN cur2
         DELETE REST IN cur2
   
         ** Issue the  SQL statement again.
   
         SELECT * FROM cur1 FULL OUTER JOIN cur2 ON id_1 = id_2
   
         WAIT WINDOW STR(_TALLY)+" records returned when 50 records are
          deleted;
         in cur2" 




2. Run the program, and after each Browse window appears, close the window. The WAIT WINDOW commands display the number of records and information on the number of deleted records. Deleting 50 records in the second cursor, cur2, causes the SQL-SELECT statement to return 150 records instead of 100.

Additional query words: kbVFp500abug kbSQL

Keywords :
Version : WINDOWS:5.0,5.0a
Platform : WINDOWS
Issue type : kbbug