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Re: proposal: Preference SQL

From: Jan Urbański <j(dot)urbanski(at)students(dot)mimuw(dot)edu(dot)pl>
To: "Decibel!" <decibel(at)decibel(dot)org>
Cc: Postgres - Hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: proposal: Preference SQL
Date: 2008-06-03 22:24:59
Message-ID: 4845C4BB.50608@students.mimuw.edu.pl (view raw or flat)
Thread:
Lists: pgsql-hackers
Decibel! wrote:
> On May 29, 2008, at 6:08 PM, Jan Urbański wrote:
>> Preference SQL is an extension to regular SQL, that allows expressing 
>> preferences in SQL queries. Preferences are like "soft" WHERE clauses. 

> This seems like a subset of http://pgfoundry.org/projects/qbe/ ... or do 
> I misunderstand?

I skimmed through the QBE howto, and I think it's actually far from it. 
The thing that closely resembles preference clauses is the SKYLINE OF 
operator, mentioned eariler in the thread - there is some archives 
coverage on it.

I'm still working on producing a comparision of preference SQL and the 
skyline operator, more to follow soon.

-- 
Jan Urbanski
GPG key ID: E583D7D2

ouden estin


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