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09/01/2002 09:08:48
Hilmar Zonneveld
Independent Consultant
Cochabamba, Bolivie
 
Information générale
Forum:
Visual FoxPro
Catégorie:
Base de données, Tables, Vues, Index et syntaxe SQL
Divers
Thread ID:
00601821
Message ID:
00602458
Vues:
42
>If someone (like you) thinks this can be improved regarding response I'd really like to learn from it, but sadly (for you) it just aint necessary. So I'm right from the start, or let's say I have a headstart.

Well, I wasn't trying to improve your program, but, in general, point to several alternatives.

> ... Therefor obviously all the (index) records have to be downloaded first.

Depending on the condition, and available indices. If I issue [SELECT * FROM ARTICLE WHERE ARTCODE = "123"], that is, starts with "123", VFP will get the index keys for only the records that match this criterion. Oh, of course, it will have to look at a few non-matching keys first - but because of the tree-like structure of the index, VFP doesn't load the entire index. Just as it doesn't need to look at every record if you do a SEEK. Otherwise, it would just be too slow - which it isn't.

Hilmar.
Difference in opinions hath cost many millions of lives: for instance, whether flesh be bread, or bread be flesh; whether whistling be a vice or a virtue; whether it be better to kiss a post, or throw it into the fire... (from Gulliver's Travels)
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