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SQLing over the net
Message
De
19/07/2001 11:24:18
Hilmar Zonneveld
Independent Consultant
Cochabamba, Bolivie
 
 
À
19/07/2001 11:17:03
Information générale
Forum:
Visual FoxPro
Catégorie:
Base de données, Tables, Vues, Index et syntaxe SQL
Divers
Thread ID:
00532545
Message ID:
00532612
Vues:
10
>>>We're working with SET DELETE ON, and I'm my book and from what I was told in several years, that we should have a tag on DELETED(). Unless, this has changed in the last versions. Isn't it the case? Any comment on that?
>>
>>Michel, basically nothing has changed. If you have a tag on Deleted(), or on any other expression that returns many records for part of a condition, the query is fully optimized, and therefore slow.
>
>The number of records returned on those queries is quite small. It doesn't exceed 400 records.

Out of a total reccount() of how many? Precisely if you select, say, 400 records out of a total of 1e6 records, the fully optimized query is slow - if any elemental condition, including the implicit "AND NOT DELETED()", returns too many records.

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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