FIX: Default Value Not Evaluated Properly Using Stored Procs

• Microsoft Visual FoxPro for Windows, version 3.0

SYMPTOMS

Under specific circumstances where two columns are calculating default values, a stored procedure may not be executed rapidly enough resulting in default values being inserted into a table's fields instead of the data generated by the stored procedure.

CAUSE

If the stored procedure that calculates the default value takes too long, a default of 0 is used for numeric fields. This is a result of a timing issue, and not a coding issue.

STATUS

Microsoft has confirmed this to be a problem in the Microsoft products listed at the beginning of this article. This problem was corrected in Visual FoxPro 3.0b for Windows.

MORE INFORMATION

The following code, when run using Visual FoxPro 3.0, demonstrates the behavior noted in this article. After a few records, the program will fail with one of several error messages. Using Visual FoxPro 3.0b, this code runs successfully.

Steps to Reproduce Problem

1. Place the following two functions into a program file called Bug.sp:

   
      FUNCTION spIncr
         PARAMETER cAliasName, cFname
         PRIVATE iNewVal
         lOldDel = SET ("DELETED")
         SET DELETED OFF
         SELECT MAX(&cFname) FROM (cAliasName) INTO ARRAY tmparr
         SET DELETED &lOldDel
         IF (_TALLY = 0)
           RETURN 1
         ENDIF
         iNewVal = tmparr(1) + 1
         RETURN iNewVal
      ENDFUNC
   
      FUNCTION spDefVal
         PARAMETER cAliasName, cFname, aDefRetVal
         PRIVATE aNewVal
         aNewVal = .NULL.
         ON Error *
         aNewVal = aDefRetVal
         aNewVal = &cAliasName..&cFname
         ON Error
         RETURN aNewVal
      ENDFUNC 




2. Execute the following code from a second .prg file:

   
      SET SAFETY OFF
      CLOSE DATABASE ALL
      CREATE DATABASE 'bugreport.DBC'
      APPEND PROCEDURES FROM 'bug.sp'
      COMPILE DATABASE bugreport.DBC
      CREATE TABLE 'bug' (NR1 I NOT NULL Default spIncr("bug","nr1"), ;
                         NR2 I NOT NULL Default spDefVal("anytable", ;
                         "anyfield",0))
      ALTER TABLE 'bug' ADD PRIMARY KEY NR1 Tag NR1
      INDEX ON NR2 Tag NR2
   
      USE bug
      BROWSE NOWAIT
      FOR idat = 1 TO 200
         KEYBOARD "{CTRL+Y}" && Append blank
      NEXT 

Additional query words: VFoxWin buglist3.00 fixlist3.00b fail

Keywords : FxprgTable
Version : WINDOWS:3.0
Platform : WINDOWS
Issue type :