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What is benefit of Local Views in apps
Message
Information générale
Forum:
Visual FoxPro
Catégorie:
Codage, syntaxe et commandes
Divers
Thread ID:
01044695
Message ID:
01044726
Vues:
12
Hi,

> why my some SQL 's take s alot of time.

Executing a view against a DBF table and running a SQL statement directly both take about the same time. If a SQL statement is slow, the corresponding view would be just as slow, and vice versa.

If a query takes a long time there are three common reasons:

- The query isn't optimized. You can use SYS(3054,12) to view optimization details.

- The result set is to big, like a SELECT * without a WHERE clause. The only solution here is to reduce the number of records you retrieve.

- The query contains calculation on a huge number of records. One possible approach is to calculate intermediate results in a trigger and query against the intermediate results instead of the original table.

Maybe you can post one example for a SQL statement that is slow?
--
Christof
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