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Uniqueness of index violation
Message
De
11/09/1997 11:21:26
Larry Long
ProgRes (Programming Resources)
Georgie, États-Unis
 
 
À
10/09/1997 19:00:16
Information générale
Forum:
Visual FoxPro
Catégorie:
Codage, syntaxe et commandes
Divers
Thread ID:
00049180
Message ID:
00049533
Vues:
62
>Erik,
>
>------ huge snip
>>
>>I occasionally use a filter on indexes, but didn't think that it was allowed on primary indexes. Apparently so, but this leaves me pretty confused as to the definition of a primary key in the first place. I mean, I thought that an neforced unique key was just that... an enforced unique key. Can anyone clear this up for me?
>>
>>Erik
>____ end snip
>
>I guess its a bit like driving a car. You *could* drive on the other side of the road if you wanted to, even though you know you shouldn't.
>
>I see Primary/Candidate indexes in rahter the same way - there are things you *CAN* do, but it doesn't mean you should do them.
>
>regards,
>Jim N
As a general rule I have started doing the following with all of my tables as a part of a personal standardization to allow for the use of both the SQL update methods (update record and delete/insert). I came up with this to be able to keep transactional record of all the changes made to a table. I would like some feed back....

All my tables have...
1) a field called "keyfield" character(18)
2) at least 3 tags
TAG NAME INDEX TYPE EXPRESSION FILTER
primary primary keyfield not deleted()
keyfield candidate keyfield
isdeleted reguar deleted()
3) keyfield default value = dtos(date())+sys(2015), which generates a unique key that I am 99.9% sure will always be unique.

This way I can have a field that is normally unique for example SS#, but allows it to be changed without changing the primary field for that record.
L.A.Long
ProgRes
lalong1@charter.net
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