category -> subcategory ->subsubcategory system

[eluser]kmunky[/eluser]
thanks @jedd for your reply. I didn't check on forum yet but i was thinking on something, to create a base controller and the first section of the url be it's name; the argument for that controller to be the last section of the url. now...my questions are:
1. do you think that the implementation of this system will be possible, will it be reliable?
2. how can i generate the url? i'm thinking of using mysql nested set model or it's doctrine equivalent (i'm not quite sure how it works but i'll focus on it), or is there a better way to do this without database interrogation ?

many thanks