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What are the best indexes to have for a filter ?
Message
De
11/01/2005 06:40:02
 
Information générale
Forum:
Visual FoxPro
Catégorie:
Base de données, Tables, Vues, Index et syntaxe SQL
Versions des environnements
Visual FoxPro:
VFP 8 SP1
OS:
Windows XP SP2
Database:
Visual FoxPro
Divers
Thread ID:
00975956
Message ID:
00975974
Vues:
9
Yes, you will not need the combined index.

If you must set a filter which can not be completely optimized, it's important to put the search criteria which can be optimized first. Here are a few examples of searchec which can be optimized:

SET FILTER TO Department=cDep and Section=cSec and Unit=cUnit
SET FILTER TO Department=cDep and ((Section=cSec and Unit=cUnit1) or (Section=cSec and Unit=cUnit2))
SET FILTER TO Department=cDep and Section=cSec and (Unit=cUnit1 or Unit=cUnit2)
SET FILTER TO (Department=cDep1 and Section=cSec1 and Unit=cUnit1) or (Department=cDep2 and Section=cSec2 and Unit=cUnit2)


>Ok so i will create three separate index tags. Does this mean i do not need an dditional index which has the 3 fields concatenated together (department+section+unit) ?
>
>What do you mean by examples of records ? You want to know the fields or the data in the table ?
>
>Thanks again
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