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How much data returned
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03/05/2006 00:09:32
 
 
Information générale
Forum:
Visual FoxPro
Catégorie:
Base de données, Tables, Vues, Index et syntaxe SQL
Divers
Thread ID:
01118142
Message ID:
01118651
Vues:
20
Hi Naomi,
>Do you know if filtered indexes allow optimization in VFP9 SP1?

AFAIR a filtered index ( FOR...) or one with "not" in its expresion
is not rushmore-usable.

Most of the time a single compound index is faster for querying or joining
(iif(iActive_flag, "1", "0") + cTrans_fk)
but "overindexing" slows down insert/update operation. Since changes in PK/FK are
probably not happening very often, you'ld have to decide if the speed gain
from using only one compound rushmore bitmap vs. 2 single bitmaps or
vs. one single bitmap and record checks on the logical field is worth
the added overhead writing to the cdx.

regds

thomas
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