FIX: Using RI Builder & Long Table Names Makes Triggers Fail

ID: Q142313

3.00 3.00b WINDOWS kbtool kbbuglist kbfixlist

The information in this article applies to:

Microsoft Visual FoxPro for Windows, versions 3.0 and 3.0b

SYMPTOMS

Using the RI Builder's code along with tables that have long table names and Private datasessions results in triggers constantly failing. The underlying error causing the triggers to fail is Error 1 "File <file_name> does not exist."

CAUSE

There are two causes. First the SET DATABASE command is scoped to Private Datasessions. Thus, there is no Database current and the appropriate database must be current for Visual FoxPro to be able to resolve long table names. Second, the Referential Integrity (RI) Builder does not take this previous issue into account.

WORKAROUND

Modify the RIOPEN procedure the RI Builder created. The modifications would consist of finding the Database the table with the long table name belongs to, using CURSORGETPROP(), SET DATABASE to this Database. Let the RIOPEN routine open the table. Then use SET DATABASE to set the database back to the original database if any.

Example Workaround

To work around this problem, make the following modifications to the RIOPEN Procedure:

1. Copy the entire RIOPEN procedure, and paste it below the "__RI_FOOTER"

2. Add the following variables to the copied RIOPEN's LOCAL declarations:

   __lcCurDBC, __tcOldTable

3. Insert the following lines immediately after the copied RIOPEN's LOCAL

   declarations:

   && Replace any spaces in Long Table name with "_".
   && because this is what VFP does in the DE, Aliases
   && are not allowed to contain spaces.
   __tcOldTable=tcTable
   tcTable=STRTRAN(ALLTRIM(tcTable)," ","_")

   && Find the DBC name the Table belongs to
   __lcCurDBC=SET('DATABASE') &&Get any current DBC
   __lcDBCName=CURSORGETPROP('DATABASE',tcTable) && Get Database Name

   __lcDBCName=substr(__lcDBCName,rat('\',__lcDBCName)+1) &&Remove path
   __lcDBCName=substr(__lcDBCName,1,rat('.',__lcDBCName)-1) &&Remove '.DBC'

   SET DATABASE TO (__lcDBCName)

   && Restore original value, the USE needs the actual Long Table name
   tcTable=__tcOldTable

4. Insert the following line immediately after the first ENDIF of the

   copied RIOPEN procedure:

   && Set back to original DBC
   SET DATABASE TO &__lcCurDBC

STATUS

Microsoft has confirmed this to be a problem in the Microsoft products listed at the beginning of this article. This problem has been fixed in Visual FoxPro 5.0 for Windows.

MORE INFORMATION

Steps to Reproduce Problem

1. Create a new database with a Parent Child Persistent Relation, and give

   the parent table a long table name.

2. Set the RI Builder so that there is RESTRICT on the Child table's

   Insert.

3. Create a new form, and add both tables to its Data Environment.

4. Set the Child Cursors's BuffermodeOverride property to 5.

5. Set the form's DataSession property to 2-Private Datasession.

6. Add the child table's Foreign Key to the Form.

7. Add a Command button to the form. Set its Caption property to Add, and

   Add the following code to its Click event:

   SELECT <child table>
   APPEND BLANK
   THISFORM.REFRESH

8. Add another Command button to the form. Set its caption property to

   Save, and add the following code to its Click event:

   SELECT<child table>
   IF .NOT. TABLEUPDATE(.T.,.T.)
      =TABLEREVERT(.T.) &&Revert the change
      IF TYPE('gaErrors[1,1]') <> 'L'
         =MESSAGEBOX('Trigger Failed - '+gaErrors[1,2],0,;
           'Data Entry Error/Trigger Failed')
      ENDIF
      GO TOP
   ENDIF
   THISFORM.REFRESH

9. Run the form. Click the Add button, and type in a value that is not in

   the Parent's Primary Key. Click the "Save" button.

KBCategory: kbtool kbbuglist kbfixlist KBSubcategory: FxtoolBuilder VFoxWin buglist3.00 buglist3.00b fixlist5.00 Additional reference words: 3.00 3.00b *

Keywords          : kbVFp kbVFp300bbug kbVFp500fix buglist3.00 FxtoolBuilder kbbuglist kbfixlist
Version           : 3.00 3.00b
Platform          : WINDOWS