[plug] heirachal data in relational databases

[Craig Ringer]

Hi folks

I recall some discussion, quite some time ago, about how to store 
heirachal trees of data in an SQL database. I think the general solution 
was established then (a self-referential table) but I've just run into 
an article that presents a really well formulated, well thought out and 
comprehensive way of doing things.

Here it is, in case anybody's still trying to improve their approach to 
that problem:

http://www.onlamp.com/pub/a/onlamp/2004/08/05/hierarchical_sql.html

--
Craig Ringer