Plateforme Level Extreme
Abonnement
Profil corporatif
Produits & Services
Support
Légal
English
Primary keys useless?
Message
 
À
31/08/1997 10:44:12
Information générale
Forum:
Visual FoxPro
Catégorie:
Autre
Divers
Thread ID:
00047863
Message ID:
00047869
Vues:
22
>I don´t know whether I´m missing anything, but I´m beginning to think that the CANDIDATE indexes (indices?) are about as useful as the old UNIQUE ones, at least if you work with SET DELETED ON.
>
>The following program should not (IMHO) produce an error, but it does:
>
> SET DELETED ON
> CREATE TABLE TRY (KEYFIELD N(3))
> INDEX ON KEYFIELD TAG KEYFIELD CANDIDATE
> INSERT INTO TRY VALUE (1)
> DELETE FOR KEYFIELD=1
> INSERT INTO TRY VALUE (1)
>
>What does this mean? For example, assume an user had (once) entered a record with a key value of 1, and later on he deleted it. If you list the table, the key 1 does not show up. If you try to SEEK it, it´s not there and FOUND() returns .F.; ok! But, after all that evidence, if you try to INSERT a new record with key 1, it fails!
>
>Am I missing anything, or is this just a VFP botch up? Opinions?

Federico,

VFP indexes include deleted records by default.
You can add Deleted() in the filter of your index.

Mike
Michael McLain
Précédent
Répondre
Fil
Voir

Click here to load this message in the networking platform