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From: marti@mint.inf.ethz.ch (Robert Marti)
Newsgroups: comp.databases
Subject: Re: how bad is oracle?
Message-ID: <24524@neptune.inf.ethz.ch>
Date: 11 Feb 91 15:56:40 GMT
References: <10737@pasteur.Berkeley.EDU> <1991Feb3.182558.14411@oracle.com> <1991Feb6.144339.10316@lgc.com> <13470@blia.sharebase.com>
Sender: news@neptune.inf.ethz.ch
Reply-To: marti@mint.inf.ethz.ch (Robert Marti)
Organization: Departement Informatik, ETH, Zurich
Lines: 18

In article <13470@blia.sharebase.com> miket@blia.sharebase.com (Mike Tossy)
writes:
>My opinion: "syntactically-based optimizer" is an oxymoron.
Maybe.  However, there is a research field called "semantic query
optimization" in which systems attempt to exploit the "knowledge"
expressed by semantic integrity constraints to simplify queries.
These optimizations may go beyond the "purely syntactic" transformations
such as pushing selection and projection operations in the parse
tree as far down as possible).  Of course, even these semantic
optimization are ultimately syntactic.

>	>>>>>>>	The above are only my opinions <<<<<<<<
Same here.

Robert Marti                      |  Phone:    +41 1 254 72 60
Institut fur Informationssysteme  |  FAX:      +41 1 262 39 73
ETH-Zentrum                       |  E-Mail:   marti@inf.ethz.ch
CH-8092 Zurich, Switzerland       |