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From: PMG <peteg@garlic.com>
Newsgroups: comp.databases.oracle.misc
Subject: Question about efficiency of Views
Date: Tue, 06 Jul 1999 22:06:58 -0700
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Hi there,

Suppose I have created a view, and then perform a select statement
against the view, with some kind of a WHERE clause.

My question is this: does the Oracle engine first perform the entire
query as delineated in the view script, and then perform a sub-select
from the view as indicated by the WHERE clause, or is the engine smart
enough to substitue the WHERE condition immediately?

IOW, is there one pass or two passes at the data? Or are they equivalent
in terms of efficiency?

TIA

Pete