RE: Re[2]: More on Subquery Madness
- From: Katz.C@xxxxxxxxxxxx
- To: jonathan@xxxxxxxxxxx, justin@xxxxxxxxxxx
- Date: Mon, 27 Sep 2004 14:22:18 -0400
To me it looks like, in the first paper he says that Oracle's implemention
is simply wrong.
In the second paper, he adds that the there are there are two kinds of
restrictive relational expressions (un-ordered ones and ordered ones). The
Gennick problem concerns an ordered restrictive relational expression.
Oracle's implentation is not right, but the cause of the problem, is that
SQL itself doesn't distinguish between these two types of expressions (so
it's not only Oracle).
(Maybe we should give Oracle implementation a null rather than a true or
false?)
Chaim
http:://www.learntorah.net
-----Original Message-----
From: Jonathan Gennick [mailto:jonathan@xxxxxxxxxxx]
Sent: Monday, September 27, 2004 1:59 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@xxxxxxxxxxx)
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@xxxxxxxxxxx
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Monday, September 27, 2004, 1:25:50 PM, Justin Cave (justin@xxxxxxxxxxx)
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@xxxxxxxxxxxxx
[mailto:oracle-l-bounce@xxxxxxxxxxxxxx]
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@xxxxxxxxxxx
JC> Join the Oracle-article list and receive one
JC> article on Oracle technologies per month by
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JC> or send email to Oracle-article-request@xxxxxxxxxxx and
JC> include the word "subscribe" in either the subject or body.
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