Q310569: PRB: Using Object.Value in UPDATE - SQL Fails

Article: Q310569
Product(s): Microsoft FoxPro
Version(s): 3.0,3.0b,5.0,5.0a,6.0,7.0
Operating System(s): 
Keyword(s): kbDatabase kbSQL kbvfp300 kbvfp300b kbvfp500 kbvfp500a kbvfp600 KbDBFDBC kbGrpDSFox kbD
Last Modified: 31-OCT-2001

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The information in this article applies to:

- Microsoft Visual FoxPro for Windows, versions 3.0, 3.0b, 5.0, 5.0a, 6.0, 7.0 
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SYMPTOMS
========

When you use an Object.Object.Value reference in an UPDATE - SQL command, you
may receive the following error message:

  Alias 'object' is not found.

This error occurs only if the Object.Object.Value syntax appears on the right
side of the assignment in the SET clause.

RESOLUTION
==========

To work around this problem, you can find other ways to use the object value.
The sample code in the "More Information" section shows some possibilities.

MORE INFORMATION
================

Steps to Reproduce Behavior
---------------------------

1. Run the following code:

  PUBLIC ofrmUpdate

  ofrmUpdate=createOBJECT("frmUpdate")
  ofrmUpdate.Show()
  RETURN

  DEFINE CLASS frmUpdate AS form

     Top = 0
     Left = 0
     Height = 115
     Width = 181
     DoCreate = .T.
     Caption = "Update Form"
     cValue = "NewValue"
     Name = "frmUpdate"

     ADD OBJECT cmdUpdate AS commandbutton WITH ;
        Top = 70, ;
        Left = 5, ;
        Height = 20, ;
        Width = 88, ;
        Caption = "UPDATE - SQL", ;
        Name = "cmdUpdate"

     ADD OBJECT txtValue AS textbox WITH ;
        Value = "Value To Set Field To...", ;
        ControlSource = "ThisForm.cValue", ;
        Height = 23, ;
        Left = 4, ;
        Top = 4, ;
        Width = 154, ;
        Name = "txtValue"

     ADD OBJECT cmdInsert AS commandbutton WITH ;
        Top = 92, ;
        Left = 5, ;
        Height = 20, ;
        Width = 88, ;
        Caption = "INSERT INTO", ;
        Name = "cmdInsert"

     ADD OBJECT cmdBrowse AS commandbutton WITH ;
        Top = 82, ;
        Left = 96, ;
        Height = 20, ;
        Width = 62, ;
        Caption = "BROWSE", ;
        Name = "cmdBrowse"

     ADD OBJECT txtKey AS textbox WITH ;
        Alignment = 3, ;
        Value = 2, ;
        Height = 23, ;
        Left = 160, ;
        Top = 4, ;
        Width = 19, ;
        Name = "txtKey"

     PROCEDURE Load
        CREATE TABLE tblUpdate (cField1 C(25), iField1 I)
        INSERT INTO tblUpdate VALUES ("Hello", 1)
        INSERT INTO tblUpdate VALUES ("GoodBye", 2)
        INSERT INTO tblUpdate VALUES ("So long", 3)
        INSERT INTO tblUpdate VALUES ("Adios", 4)
        INSERT INTO tblUpdate VALUES ("Greetings!", 5)
     ENDPROC

     PROCEDURE cmdUpdate.Click
        *!* The following lines will cause the error.
        UPDATE tblUpdate ;
           SET cField1 = ThisForm.txtValue.VALUE ;
           WHERE iField1 = 2
        *!* UPDATE tblUpdate ;
           SET cField1 = THIS.PARENT.txtValue.VALUE ;
           WHERE iField1 = 2

        *!* The following lines will not cause the error.
        *!* UPDATE tblUpdate ;
           SET cField1 = EVALUATE("THIS.PARENT.txtValue.VALUE") ;
           WHERE iField1 = 2
        *!* UPDATE tblUpdate ;
           SET cField1 = ThisForm.cValue ;
           WHERE iField1 = 2
        *!* UPDATE tblUpdate ;
           SET cField1 =  EVALUATE("THIS.PARENT.txtValue.VALUE") ;
           WHERE iField1 = ThisForm.txtKey.VALUE
        *!* UPDATE tblUpdate ;
           SET cField1 = ThisForm.cValue ;
           WHERE iField1 = ThisForm.txtKey.VALUE
        *!* The following two lines, taken together, do not cause the error.
        *!* loTextbox = ThisForm.txtValue
        *!* UPDATE tblUpdate ;
           SET cField1 = loTextbox.Value ;
           WHERE iField1 = 2
     ENDPROC

     PROCEDURE cmdUpdate.Error
        LPARAMETERS nError, cMethod, nLine
        =MESSAGEBOX("Error in UPDATE command: " + MESSAGE() )
        RETURN
     ENDPROC

     PROCEDURE cmdInsert.Click
        INSERT INTO tblUpdate ;
           VALUES (ThisForm.txtValue.Value, RECCOUNT() + 1 )
     ENDPROC

     PROCEDURE cmdBrowse.Click
        BROWSE
     ENDPROC
  ENDDEFINE

2. Uncomment each UPDATE statement in turn to see the problem and the various
  workarounds.

Additional query words:

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Keywords          : kbDatabase kbSQL kbvfp300 kbvfp300b kbvfp500 kbvfp500a kbvfp600 KbDBFDBC kbGrpDSFox kbDSupport kbvfp700 
Technology        : kbVFPsearch kbAudDeveloper kbVFP300 kbVFP300b kbVFP500 kbVFP600 kbVFP700 kbVFP500a
Version           : :3.0,3.0b,5.0,5.0a,6.0,7.0
Issue type        : kbprb

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