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Unique ID Violated With Add/Delete
Message
De
15/06/1998 14:43:42
 
 
À
15/06/1998 14:39:08
Information générale
Forum:
Visual FoxPro
Catégorie:
Codage, syntaxe et commandes
Divers
Thread ID:
00108257
Message ID:
00108317
Vues:
46
>>>You bring up a question in my mind that I've had for awhile. Are there any *real* benefits to using unique or candidate keys. I've yet to come up with anything that outweighs the annoyances.< s >
>>
>>Absolutely there are. To name two (and there are others) that apply to VFP:
>>
>>1) Normalization. You need a unique key that will never change.
>>2) Scalability. SQL Server and Oracle DEMAND unique, primary keys.
>>3) Conflict. A unique violation may alert you to other errors in data mgmt.
>
>
>Of course there is a need for a unique key, but what is the need for an index that is of type Primary or Candidate when a regular index will do just as well (and allow me control to fix problems that should arise like the start of this thread)? < s >

Hmmm...I'd have to think about that....my gut instinct is to respond "are you nuts??" but that is high-tower database theory talking (just kidding). A unique key identified as the Primary key is a central tenet to relational theory. You don't HAVE to have one in VFP standalone if you really don't want to...
------------------------------------------------
John Koziol, ex-MVP, ex-MS, ex-FoxTeam. Just call me "X"
"When the going gets weird, the weird turn pro" - Hunter Thompson (Gonzo) RIP 2/19/05
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