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Re: A technical question about VIEWS

From: Keystroke <keystrk_at_feist.com>
Date: 1997/04/15
Message-ID: <33540ac5.668557@news.feist.com>#1/1

On Tue, 15 Apr 1997 08:24:08 GMT, Clark Mason <cmason_at_aai.arco.com> wrote:

>> The view's query is not dynamic, you are building an intermediate table. A
>> view reacts like a subquery. It always
>> returns the same solution set regardless of what else you specify in the
>> query. So the answer is that Oracle will first create the view will 10,000
>> rows. Then process the rest of the query against it.
>>
>> That's how I understand it.

in Oracle Book: \oracle\doc\server\72\svtuning.obd Chapt 6 - Page 1 - under heading: How Oracle Optimizes SQL Statements third list entry it says:

view merging	For a SQL statement that accesses a view,
		the optimizer often merges the query in
		the statement with that in the view and
		then optimizes the result.

What is the source of the position that it returns all the data from the view first? Is there some flakey DBMS out there (sybase?) that does it this way, and everyone assumes Oracle does it that way also? Received on Tue Apr 15 1997 - 00:00:00 CDT

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