PRB: "Update Conflict" Message When Modifying SQL Server Data

• Microsoft Visual FoxPro for Macintosh, version 3.0b
• Microsoft Visual FoxPro for Windows, versions 3.0, 3.0b, 5.0, 5.0a, 6.0

SYMPTOMS

An "Update Conflict" message appears when attempting to modify or delete a record, contained in an updatable cursor, SELECTed from a SQL Server table.

CAUSE

This behavior occurs when SQL Server does not return a message indicating the number of rows returned by a statement. SQL Server does not return a message indicating the number of rows affected by a statement after the following commands have been executed on SQL Server:

   sp_configure "user options", 512
   SET NOCOUNT ON 

RESOLUTION

Check the value of SQL Server's global user options configuration setting, before allowing manipulation of SQL Server tables through an updateable cursor.

The following code snippet illustrates how to obtain the current global SQL Server "user options" configuration setting:

Sample Code

   gnConnHandle=SQLSTRINGCONN('DRIVER={SQL Server};' + ;
      'SERVER=SPHINXSQL;DATABASE=ALMIS;UID=sa;PWD=')
   sqlcommand="USE ALMIS"
   =SQLEXEC(gnConnHandle,sqlcommand)
   testval=0
   sqlcommand="sp_configure 'user options'"
   testval=SQLEXEC(gnConnHandle,sqlcommand,'mytest')
   oldvalue=0
   IF testval>0
      SELECT mytest
      oldvalue=config_value
      BROW
   ENDIF
   IF oldvalue<>512
      * Insert code here that would allow the user to view and modify data
      * contained in an updateable cursor.
   ELSE
      * Insert code here that would allow the user to view but not modify
      * data in a cursor.
   ENDIF
   =SQLDISCONNECT(gnConnHandle) 

MORE INFORMATION

The "Update Conflict" message indicates that an optimistic locking conflict has been detected while trying to update a view.

The SQL Server stored procedure, sp_configure, displays or changes global SQL Server configuration settings. EXECuting the sp_configure using the following syntax turns off the message, returned at the end of each statement, indicating the number of rows affected by the statement:

   sp_configure "user options", 512 

   SET NOCOUNT ON 

Steps to Reproduce Behavior

1. Create a program file called "SQLDEMO.PRG", using the following code:

   
         PUBLIC ox
         ox=CREATEOBJECT('test1')
         ox.SHOW
   
         DEFINE CLASS test1 AS FORM
            TOP = 15
            LEFT = 37
            HEIGHT = 250
            WIDTH = 360
            DOCREATE = .T.
            CAPTION = "Form1"
            NAME = "Form1"
   
            ADD OBJECT command1 AS COMMANDBUTTON WITH ;
               TOP = 216, ;
               LEFT = 120, ;
               HEIGHT = 25, ;
               WIDTH = 120, ;
               CAPTION = "\<Delete Record", ;
               NAME = "Command1"
   
            ADD OBJECT grid1 AS GRID WITH ;
               HEIGHT = 145, ;
               LEFT = 24, ;
               TOP = 24, ;
               WIDTH = 312, ;
               NAME = "Grid1"
   
            PROCEDURE LOAD
               PUBLIC gnConnHandle, testval, old_user_option
               gnConnHandle=SQLSTRINGCONN('DRIVER={SQL Server};' + ;
                  'SERVER=SPHINXSQL;DATABASE=PUBS;UID=sa;PWD=')
               *!*
               *!* You may have to change the SERVER and DATABASE
               *!* Values. Make sure user specific UID and PWD
               *!* values are specified.
               *!*
               SQLCommand="USE PUBS"
               *!*
               *!* If using a different Database Substitute PUBS
               *!* for the name of the Database to be used.
   			*!*
               =SQLEXEC(gnConnHandle,SQLCommand)
               testval=0
               *!* Retrieve current global user options settings.
               SQLCommand="sp_configure 'user options'"
               testval=SQLEXEC(gnConnHandle,SQLCommand,'mytest')
               old_user_option=0
               IF testval>0
                  SELECT mytest
                  old_user_option=config_value
               ENDIF
               *!* Comment the lines indicated below and the updates succeed,
               *!* unless the global SQL Server user options configuration
               *!* is 512 and SET NOCOUNT ON has been issued
               *!*
               *!*  TOP OF LINES TO COMMENT
               SQLCommand="sp_configure 'user options',512"
               testval=SQLEXEC(gnConnHandle,SQLCommand)
               SQLCommand="reconfigure"
               =SQLEXEC(gnConnHandle,SQLCommand)
               SQLCommand="set nocount on"
               testval=SQLEXEC(gnConnHandle,SQLCommand)
               *!*  END OF LINES TO COMMENT
               *!*
               *!*  Create a table for testing in the Pubs database.
               SQLCommand="CREATE TABLE TESTING (STORE_ID CHAR(5) NOT NULL," +;
                  " STOR_NAME CHAR(35) NOT NULL)"
               testval=SQLEXEC(gnConnHandle,SQLCommand)
               *!*  Insert three records into the test table
               FOR i=1 to 3
                SQLCommand="INSERT INTO TESTING VALUES ('" + REPLICATE("0",4) +;
                ALLTRIM(STR(i)) + "','Store Number " + ALLTRIM(STR(i)) + "')"
                testval=SQLEXEC(gnConnHandle,SQLCommand)
               NEXT
               SQLCommand="SELECT * FROM TESTING"
               testval4=SQLEXEC(gnConnHandle,SQLCommand)
               SELECT sqlresult
               =AFIELDS(testresult)
               szKeyList=testresult[1,1]
               szFieldList=""
               szUpdateList=""
               *!*  Store the field names to a comma delimited list.
               FOR i=1 TO ALEN(testresult,1)
                  IF LEN(ALLTRIM(szFieldList))>0
                     szFieldList=ALLTRIM(szFieldList)+","
                  ENDIF
                  szFieldList=szFieldList+ALLTRIM(testresult[i,1]) + ;
                     " DBO.TESTING."+ALLTRIM(testresult[i,1])
                  IF LEN(ALLTRIM(szUpdateList))>0
                     szUpdateList=ALLTRIM(szUpdateList)+","
                  ENDIF
                  szUpdateList=szUpdateList+ALLTRIM(testresult[i,1])
               NEXT
               *!*  Set the cursor so that it is updatable
               =CURSORSETPROP("Tables", 'DBO.TESTING')
               =CURSORSETPROP("UpdateNameList",szFieldList)
               =CURSORSETPROP("KeyFieldList",szKeyList)
               =CURSORSETPROP("UpdatableFieldList", szUpdateList)
               =CURSORSETPROP("WhereType",1)
               =CURSORSETPROP("SendUpdates", .T.)
            ENDPROC
   
            PROCEDURE UNLOAD
               =TABLEREVERT(.T.)
               *!* Drop the test table that was created from the Pubs Database.
               SQLCommand="DROP TABLE TESTING"
               =SQLEXEC(gnConnHandle,SQLCommand)
               *!*  Reset SQL Server Global user option configuration settings
               *!*  to original values.
               SQLCommand="sp_configure 'user options'," + ;
                  ALLTRIM(STR(old_user_option))
               =SQLEXEC(gnConnHandle,SQLCommand)
               SQLCommand="reconfigure"
               =SQLEXEC(gnConnHandle,SQLCommand)
               SQLCommand="set nocount off"
               =SQLEXEC(gnConnHandle,SQLCommand)
               =SQLDISCONN(gnConnHandle)
            ENDPROC
   
            PROCEDURE command1.CLICK
               DELETE
               SKIP
               THISFORM.REFRESH
            ENDPROC
         ENDDEFINE 




2. Type the following in the Command window:

   
         DO SQLDEMO 




3. Click the Command Button captioned "Delete Record".



4. A message box with the message "Update Conflict" appears. Click Ignore.



5. Close the form.

REFERENCES

SQL Reference Help; search on: "sp_configure"

SQL Reference Help; search on: "SET"

(c) Microsoft Corporation 1998, All Rights Reserved. Contributions by John Desch, Microsoft Corporation.

Additional query words: kbDSupport kbDSE

Keywords : kbClient KbClientServer kbDatabase kbVFp KbDBFDBC
Version : MACINTOSH:3.0b; WINDOWS:3.0,3.0b,5.0,5.0a,6.0
Platform : MACINTOSH WINDOWS
Issue type : kbprb