Re: SQL99 Hierarchical queries - Mailing list pgsql-hackers

From Josh Berkus
Subject Re: SQL99 Hierarchical queries
Date
Msg-id 200502282252.17096.josh@agliodbs.com
Whole thread Raw
In response to SQL99 Hierarchical queries  (Evgen Potemkin <eugen.potemkin@gmail.com>)
List 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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