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Q142283: PRB: Uniqueness of Index Violated When Creating Primary Index

Article: Q142283
Product(s): Microsoft FoxPro
Version(s): WINDOWS:3.0,3.0b
Operating System(s): 
Keyword(s): 
Last Modified: 07-APR-2000

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The information in this article applies to:

- Microsoft Visual FoxPro for Windows, versions 3.0, 3.0b 
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SYMPTOMS
========

After you create a Primary Index for a table that is populated with records and
choose to make the structure changes permanent, the following error message
appears:

  Uniqueness of index <name> is violated.

CAUSE
=====

More than one record, including any deleted records, contain the same value
within the field being used for the Primary Index. This also applies to the
existence of more than one blank record, whether marked for deletion or not.

RESOLUTION
==========

Eliminate any use of the same value within multiple records. There are many
methods you could use, but perhaps the easiest is to use a query. The following
example query will generate a cursor that contains a list of the values that
occur in more than one record of a table:

     SELECT <field name> FROM <table name>;
        GROUP BY <field name>;
        HAVING COUNT(<field name>) > 1

If duplicate records have been marked for deletion and you prefer that the table
not be packed to eliminate them, the Primary Index must contain the following
filter to ignore the deleted records:

     !DELETED()

For more information about reusing deleted primary key values, please see the
following article in the Microsoft Knowledge Base:

  Q139756 Cannot Reuse Deleted Primary Key Values in Visual FoxPro

STATUS
======

This behavior is by design.

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

The intent of a primary index is to never permit duplicate values on the
specified fields. For more information about primary indexes, search for
"primary index" in the Visual FoxPro Help file.

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

1. Create a new table that has two fields. In this case, the table is called
  States and the fields are Fullname (Character, 15) and Abbrev (Character, 2).

2. Add the following records to the table:

  Fullname     Abbrev
  -------------------
  Alabama      AL
  Alaska       AK
  Arizona      AZ
  Arkansas     AR

3. Add two blank records to the table, and mark them for deletion, but do not
  pack the table.

4. On the Window menu, click View Window, and if the States table isn't open,
  click Open. Then select it.

5. Click the Properties button, and from the Work Area Properties window, click
  the Modify button.

6. Click the Index tab in the Table Designer, and enter state for the Name, set
  Primary as the Type, and Fullname for the Expression.

7. Click OK. Within the message box asking to make structure changes permanent,
  click Yes. At this point, the following error appears:

  Uniqueness of index state is violated.

Additional query words: VFoxWin

======================================================================
Keywords          :  
Technology        : kbVFPsearch kbAudDeveloper kbVFP300 kbVFP300b
Version           : WINDOWS:3.0,3.0b
Issue type        : kbprb

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