RE: Re[2]: More on Subquery Madness

How can both be true? If the SQL language does not allow you to specify the proper relational logic, how can the optimizer be faulted for improperly guessing at the developer's intention?

Arguably, in fact, Oracle does allow you to specify the proper relational logic through the use of the NO_MERGE hint. Not the prettiest option, certainly, but it does seem to provide the necessary extension to SQL's vocabulary.

Justin Cave
Distributed Database Consulting, Inc.
http://www.ddbcinc.com/askDDBC

-----Original Message-----

From: oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Jonathan Gennick
Sent: Monday, September 27, 2004 2:16 PM To: Justin Cave
Cc: Oracle-L Freelists
Subject: Re[2]: More on Subquery Madness

Monday, September 27, 2004, 1:25:50 PM, Justin Cave (justin_at_askddbc.com) wrote:
JC> Reading Date's two replies, it seems that he reaches the opposite conclusion
JC> in the later discussion-- SQL is unable to express certain relational JC> algebra concepts properly-- than he did originally-- Oracle's optimizer is
JC> behaving incorrectly.

I suspect he would say that both are true :-)

Best regards,

Jonathan Gennick --- Brighten the corner where you are http://Gennick.com * 906.387.1698 * mailto:jonathan@gennick.com

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Monday, September 27, 2004, 1:25:50 PM, Justin Cave (justin_at_askddbc.com) wrote:
JC> Reading Date's two replies, it seems that he reaches the opposite conclusion
JC> in the later discussion-- SQL is unable to express certain relational JC> algebra concepts properly-- than he did originally-- Oracle's optimizer is
JC> behaving incorrectly. I don't see him say that he has changed his mind, JC> though... Am I missing some subtlety here?

JC> Justin Cave  
JC> Distributed Database Consulting, Inc.
JC> http://www.ddbcinc.com/askDDBC

JC> -----Original Message-----
JC> From: oracle-l-bounce_at_freelists.org
[mailto:oracle-l-bounce_at_freelists.org]

JC> On Behalf Of Jonathan Gennick
JC> Sent: Monday, September 27, 2004 9:00 AM
JC> To: Oracle-L Freelists
JC> Subject: More on Subquery Madness

JC> Chris Date surprised me by writing some more on the topic:

JC> http://www.dbdebunk.com/page/page/1409199.htm JC> x

JC> I actually found his follow-up here more enlightening than
JC> his first round of thoughts. It's a good, thought-provoking
JC> read.

JC> Best regards,

JC> Jonathan Gennick --- Brighten the corner where you are JC> http://Gennick.com * 906.387.1698 * mailto:jonathan@gennick.com

JC> Join the Oracle-article list and receive one
JC> article on Oracle technologies per month by 
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JC> http://five.pairlist.net/mailman/listinfo/oracle-article, 
JC> or send email to Oracle-article-request_at_gennick.com and 
JC> include the word "subscribe" in either the subject or body.

JC> --
JC> http://www.freelists.org/webpage/oracle-l

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http://www.freelists.org/webpage/oracle-l Received on Mon Sep 27 2004 - 13:22:16 CDT