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Best way to index
Message
De
05/04/2000 19:12:32
 
Information générale
Forum:
Visual FoxPro
Catégorie:
Base de données, Tables, Vues, Index et syntaxe SQL
Divers
Thread ID:
00355970
Message ID:
00355987
Vues:
26
As I stated before, VFP does not use variable length indexes. If you use Trim in the index tag, the fields will be trimmed, but padded with spaces on the end to fill up to what the field length should be.

PF

>What if you're not combining fields? If you are only indexing on one field, does it make sence to use AllTrim() on that index?. Does it make it easier to use:
seek("ThisData") instead of Seek("ThisData      ")?
>
>>Big rule of thumb, or just a plain ole' big no-no is to use Trim in indexes. Foxpro does not work with variable length indexes.
>>
>>Example
>>
>>Column 1 Column 2
>>"10" "1"
>>"1" "01"
>>
>>If you have index of trim(column1) + trim(column2), both index keys from above will be "101".
>>
>>PF
>>
>>>Is there a rule of thumb to follow when using index expressions? Is it common to index on something like Upper(AllTrim(FieldName))? Are there performance issues in doing this?
>>>Any thoughts?
>>>TIA

(On an infant's shirt): Already smarter than Bush
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