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What are the best indexes to have for a filter ?
Message
De
11/01/2005 10:30:34
Hilmar Zonneveld
Independent Consultant
Cochabamba, Bolivie
 
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:
00976040
Vues:
9
>Hi Tore.
>
>Sorry for the delay in answering.
>
>The problem is that if I do not use $ and filter on Department+Section+Unit, I will end up with a huge filter string. I can't build up the filter for department, section, and unit individually.
>
>If i have the three individual indexes and then do the filter as it was originally (Department+Section+Unit $ cDepSecUnit), it still won't be good ?
>
>
>Thanks

You can easily use a variable WHERE clause, with macro substitution, i.e., the "&" sign.

For example:
lcDepartment = ThisForm.TxtDepartment.Value && i.e., based on user input
if not empty(lcWhereClause)
  lcWhereClause = "Department = " + lcDepartment
endif
...
select
  ...
  where &lcWhereClause
  ...
Combining two or more expressions with AND is a little more tricky, but perhaps this gives you the general idea.
Difference in opinions hath cost many millions of lives: for instance, whether flesh be bread, or bread be flesh; whether whistling be a vice or a virtue; whether it be better to kiss a post, or throw it into the fire... (from Gulliver's Travels)
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