Walter Meester
HoogkarspelPays-Bas
Information générale
Catégorie:
Base de données, Tables, Vues, Index et syntaxe SQL
Bela,
>When you have SET DELETED on AND want to make use of the filter capability of the SQL SELECT statement"
>what type of filter capacity?
>I usually SET DELETED ON, and make many SQL SELECT with complex WHERE clauses. Only one of my tables contains deleted records. Should I make tag on deleted() in all table?
When you issue SET DELETE ON and give a command like SELECT * FROM table INTO CURSOR x and you've got a filter on deleted() VFP doesn't execute the query in the normal manner, but just reopens the table and set a filter. I this way the 'query' is executed much faster. But to accomplish this the query must be very simple (SELECT * FROM table WHERE Fully_optimizible_expression).
As these types of queries are fairly rare and mostly unwanted (it doesn't create a cursor in the temp dir so you can't say USE (DBF(Cursorname)) AGAIN ALIAS x.
Walter,
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