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Rushmore'ing substrings
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À
21/01/2003 16:24:43
Hilmar Zonneveld
Independent Consultant
Cochabamba, Bolivie
Information générale
Forum:
Visual FoxPro
Catégorie:
Base de données, Tables, Vues, Index et syntaxe SQL
Divers
Thread ID:
00743958
Message ID:
00743973
Vues:
18
>First of all, you should not have an index on alltrim(something), since this will give you a variable expression length. VFP doesn't support this, and it will put an almost arbitrary length (actually based on the first record it finds, I think).

Hilmar,
This is not true for indexes on normal fields. Because VFP has fixed length fields, the index key will be stored as if a PADR(< alltrim(field value) >,< field width >) was executed on it. Alltrim() has detrimental effects when dealing with memo fields because they are variable length. The first record will determine how long the index key expression will be. Everything after that will be padded or truncated as needed.
Larry Miller
MCSD
LWMiller3@verizon.net

Accumulate learning by study, understand what you learn by questioning. -- Mingjiao
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