Q193728: PRB: SET COLLATE TO Command Causes Inconsistent Comparisons

Article: Q193728
Product(s): Microsoft FoxPro
Version(s): WINDOWS:5.0,5.0a,6.0
Operating System(s): 
Keyword(s): 
Last Modified: 16-MAR-1999

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The information in this article applies to:

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

Comparing the equality of alphabetic characters using the UPPER() and LOWER()
functions with the collation sequence set to Czech or Hungarian, produces
incorrect results with some or all of the comparisons.

RESOLUTION
==========

One workaround is to use the double equal operator (==) when making string
comparisons.

STATUS
======

Microsoft has confirmed this to be a problem in the Microsoft products that are
listed at the beginning of this article.

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

Codepage 1250 or 852 works for a collation sequence of either Hungarian or
Czech.

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

1. In the Config.fpw file, set the codepage to 1250 as follows and restart
  Visual FoxPro:

  Codepage=1250

2. Create a program containing the following code and run the program. This code
  compares the lower case letters of the alphabet:

     MODIFY WINDOW SCREEN FONT "Courier New",10
     CLEAR
     *SET COLLATE TO "MACHINE"
     SET COLLATE TO "CZECH" && or "Hungary" with codepage of 1250
    
     ? space(2)+"Lower to Upper"+space(14)+"Upper to Lower"+space(13) ;
       +"ASC() Values"

     ? space(2)+REPLICATE("-",14)+space(14)+REPLICATE("-",14)+space(13);
       +REPLICATE("-",12)
     FOR i = 1 TO 26
        DO test WITH CHR(96 + i)
     ENDFOR

     PROCEDURE test (s)

     ? s, "Lower("+s+") to Upper("+s+"):", LOWER(s) = UPPER(s), ;
       "  Upper("+s+") to Lower("+s+"):", UPPER(s) = LOWER(s),;
       ASC(s), "=", ASC(UPPER(s)), "?"

  Comparisons using lower case letters always produce incorrect results when
  comparing values returned from the LOWER() to the UPPER() functions (?
  LOWER(s)=UPPER(s)). All of the UPPER() to LOWER() comparisons with lower case
  letters (? UPPER(s)=LOWER(s)) are incorrect except for the following
  letters:

   Letter   Decimal
   ----------------

   b        98
   f        102
   g        103
   h        104
   j        106
   k        107
   m        109
   p        112
   q        113
   v        118
   w        119
   x        120

  NOTE: The lower case "g" evaluates incorrectly when comparing UPPER() to
  LOWER() under the Hungary collation sequence.

3. Create another program and add the following code to compare the upper case
  letters of the alphabet:

     MODIFY WINDOW SCREEN FONT "Courier New",10
     CLEAR
     *SET COLLATE TO "MACHINE"
     SET COLLATE TO "CZECH" && or "Hungary" with codepage of 1250
     
     ? space(2)+"Lower to Upper"+space(14)+"Upper to ;
       Lower"+space(13)+"ASC() Values"

     ? space(2)+REPLICATE("-",14)+space(14)+REPLICATE("-",14)+space(13);
       +REPLICATE("-",12)
     FOR i = 1 TO 26
        DO test WITH CHR(64 + i)
     ENDFOR

     PROCEDURE test (s)

     ? s, "Lower("+s+") to Upper("+s+"):", LOWER(s) = UPPER(s), ;
       "  Upper("+s+") to Lower("+s+"):", UPPER(s) = LOWER(s),;
       ASC(s), "=", ASC(UPPER(s)), "?"

  Comparisons using upper case letters always produce incorrect results when
  comparing values returned from the LOWER() to the UPPER() functions (?
  LOWER(S)=UPPER(S)). All of the UPPER() to LOWER() comparisons with upper case
  letters (? UPPER(S)=LOWER(S)) are incorrect except for the following
  letters:

   Letter   Decimal
   ----------------

   B        66
   F        70
   G        71
   H        72
   J        74
   K        75
   M        77
   P        80
   Q        81
   V        86
   W        87
   X        88

  NOTE: The upper case "G" evaluates incorrectly when comparing UPPER() to
  LOWER() under the Hungary collation sequence.

4. Remove the CodePage= command from the Config.sys and change the SET COLLATE
  TO command to MACHINE. Now all the comparisons between UPPER() and LOWER()
  and LOWER() and UPPER() values are correct.

REFERENCES
==========

For additional information, please see the following articles in the Microsoft
Knowledge Base:

  Q176884 PRB: Problems with SET COLLATE and Queries with Integer Fields

  Q181085 SET COLLATE & Queries - Additional Problem Scenarios

Additional query words: kbVFp500a kbVFp500 kbVFp600 kbXBase KbDBFDBC kbDatabase kbdse kbcode

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Keywords          :  
Technology        : kbVFPsearch kbAudDeveloper kbVFP500 kbVFP600 kbVFP500a
Version           : WINDOWS:5.0,5.0a,6.0
Issue type        : kbprb
Solution Type     : kbpending

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