Walter Meester
HoogkarspelPays-Bas
Information générale
Catégorie:
Base de données, Tables, Vues, Index et syntaxe SQL
Chaim,
>Hello Andrus,
>If you have a large table and you SET DELETED ON, then you need the index on DELETED() regardless of how many records are deleted. If you do not have an index on DELETED(), VFP has to inspect each record to determine whether or not to present it. Thus, you lose all Rushmore optimization.
This is simply NOT True. If you don't have a deleted() tag, rushmore still optimizes when it can use other indexes to optimize.
If you've got an invoices table with 1 milion records in it with only a few thousands deleted, and you want to select all the records with a particular article (with an index on article) you don't need a tag on deleted() because it runs in aprox. the same time as with a tag on deleted().
I personally find indexes on deleted a waste of diskspace and performance (when it comes to appending records).
Though an index enables fox to use full optimization it is NO guarantee that it will be faster than only a partial optimization.
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