Tree structure / access rights and associations

[Tomas Vondra <tv(at)fuzzy(dot)cz>]

Hello,

in an application I was working on recently, we had to develop a system 
to grant access rights on and associate items with parts of a tree. 
Imagine for example a tree of product categories in an e-shop - you 
might want to associate items with these categories with categories 
(once you associate the item to a category, it's associated to it's 
parent category too) and grant access rights on subtrees to 
administrators (once you grant access to a category, you're granting 
access to it's subcategories too).

Inspired by the solution we developed, I've implemented a similar system 
and I'm releasing it under GPL license. All the sources (basically a set 
of triggers) along with documentation etc. can be found here:

    http://www.fuzzy.cz/databaze/index-en.php

Tomas