You can create an index on that field, and make the type "Candidate" and that should prevent duplicates.
This candidate key includes blanks so if you add a record with a blank value, that is allowed. The next record being added with a blank value would *not* be allowed. I've seen this cause trouble in older VFP systems that use an APPEND BLANK followed by a REPLACE statement. If the APPEND BLANK succeeds, but the REPLACE statement fails, you can be left with an "orphaned" blank record in the system. All subsequent "Add" operations will fail. If you use just an INSERT statement, you should be okay. On 12/01/2010 06:39 PM, Sytze de Boer wrote: > I have a client who has asked me to add a field to a table > The app is very old, but works a charm > (I think they are using sql to access the free standing table) > > They have asked for a Character field, 32 chars > THE FIELD MUST NOT ALLOW DUPLICATES > > How do go about this ? > _______________________________________________ Post Messages to: [email protected] Subscription Maintenance: http://leafe.com/mailman/listinfo/profox OT-free version of this list: http://leafe.com/mailman/listinfo/profoxtech Searchable Archive: http://leafe.com/archives/search/profox This message: http://leafe.com/archives/byMID/profox/[email protected] ** All postings, unless explicitly stated otherwise, are the opinions of the author, and do not constitute legal or medical advice. This statement is added to the messages for those lawyers who are too stupid to see the obvious.
