Re: Views on Views

The most recent releases of ORACLE can use the view definitions to generate another query, derived from yours, that aim directly at the base tables. This is done automatically. So, chances are that your query upon views happen to be just as efficient as the equivalent query on their base tables.

Despite of this smart approach, I avoid using complicated views, or views envolving functions, as the base for frequently executed queries. If your query is based on views, which, in turn, are based on functions that also call another views, for instance, a performace problem may get very hard to frame...

John Parrott <spo_at_interlog.com> escreveu no artigo <328BD999.118B_at_interlog.com>...
> I'm looking for pros and cons of using views.
>
> Does the server first execute the statement in the view against the
> entire table then perform the second select statement which might limit
> the number of rows dramatically or is the server smart enough to limit
> the rows first then perform the functions in the view only on the
> limited result set.
Received on Sun Nov 17 1996 - 00:00:00 CET