Q189598: BUG: Full Outer Join Does Not Respect Deleted Records

Article: Q189598
Product(s): Microsoft FoxPro
Version(s): WINDOWS:5.0,5.0a
Operating System(s): 
Keyword(s): 
Last Modified: 24-AUG-1999

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The information in this article applies to:

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

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Keywords          :  
Technology        : kbVFPsearch kbAudDeveloper kbVFP500 kbVFP500a
Version           : WINDOWS:5.0,5.0a
Issue type        : kbbug
Solution Type     : kbpending

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