Plateforme Level Extreme
Abonnement
Profil corporatif
Produits & Services
Support
Légal
English
Rushmore and indices
Message
 
 
À
26/09/2002 13:19:02
Information générale
Forum:
Visual FoxPro
Catégorie:
Base de données, Tables, Vues, Index et syntaxe SQL
Divers
Thread ID:
00704811
Message ID:
00704838
Vues:
19
>Is it a good idea to define a logical index in order to have an expression be optimized by rushmore or it isn't woth it?
>
>Could there be an expression be half optimized by rushmore or it's always an all or nothing situation?
>
>TIA

Queries can have Full, Partial or No optimzation.

As for whether to index a logical field, it depends on what your queries are checking for, IMO. If you are going to query for .T. and .F., depending on the query, and the distribution of values is roughly equal, then I wouldn't create an index.

VFP would probably work faster using the disciminating indexes based on the other criteria in your query and then doing a scan of that intermediate result to check the logical field. However, if the distribution is skewed in one direction and you are always going to query for the smaller part of the distribution curve, then I would create the index.

HTH.
Larry Miller
MCSD
LWMiller3@verizon.net

Accumulate learning by study, understand what you learn by questioning. -- Mingjiao
Précédent
Répondre
Fil
Voir

Click here to load this message in the networking platform