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SQL - set filter to
Message
De
10/03/2016 09:07:25
 
 
À
09/03/2016 23:08:05
Information générale
Forum:
Visual FoxPro
Catégorie:
Codage, syntaxe et commandes
Versions des environnements
Visual FoxPro:
VFP 9 SP2
OS:
Windows 7
Database:
Visual FoxPro
Application:
Desktop
Divers
Thread ID:
01632771
Message ID:
01632783
Vues:
61
>VERY interesting phenomenon - using a common data environment, using an SQL Select statement, after releasing the form it was called from, required a 'set filter to' statement to 'reset' the data to be able to 'seek' in it again without retaining a 'set filter to xyz' that was never issued! I have used SQL Select statements endlessly before, but nevvver with this result.
>
>ANY ideas??
>

The only interaction I know of between filters and SQL SELECT is the one around queries that involve a single table and are fully optimizable:

From http://www.tomorrowssolutionsllc.com/Articles/Speed%20Up%20Your%20SQL%20Code.pdf:

When a query uses a single table, has only fields from that table in the field list (and no expressions or literals), puts the results into a cursor, and can be fully optimized, VFP filters the source table rather than creating a new file on disk. In some cases, such as reporting, this isn’t a problem. But if you want to use that cursor in a subsequent query or display it in a grid, this trick causes problems.

But that shouldn't have an effect on the table itself, only the cursor that's the query result.

Tamar
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