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Re: SQL99 Hierarchical queries

From: Josh Berkus <josh(at)agliodbs(dot)com>
To: pgsql-hackers(at)postgresql(dot)org
Subject: Re: SQL99 Hierarchical queries
Date: 2005-03-01 06:52:17
Message-ID: 200502282252.17096.josh@agliodbs.com (view raw or flat)
Thread:
Lists: pgsql-hackers
Mike,

> I'm curious what kind of performance differences there would be over
> using something like the nested-set model?
>
> Would this be faster, or slower?

The answer is "yes".    ;-)

Which tree structures you use depends on what you're trying to accomplish and 
what your use case is.   There are some structures (for example, heirarchical 
org charts) for which nested sets can't be beat.   There are plenty of 
reasons to implement other tree structures, such as graphs, cycles, and 
delimited lists depending on what you're trying to depict.   

What WITH is going to "replace", if anything, is the simple adjacency list 
structure.

-- 
Josh Berkus
Aglio Database Solutions
San Francisco

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