Looking at the mptt example ​http://code.djangoproject.com/wiki/ModifiedPreorderTreeTraversal it seemed a bit complicated for a normal user to understand. So i made my own, but considering i cannot group by makes aggregate functions hard (impossible?) to make this work nice, but magic-removal made it easier. Currently only works in postgesql and only tested in 8.1. Use at will and own RISK, but if/ when you improve it i would like to see it made available.

I attach the file and give a example here. Just add fields to this and in should work.

Remember to set the TABLE variable at the top of models to appname_model.

Example using project name myproject and app name pages.

from myproject.pages.models import Page

tree = Page.manager.all() # get entire tree

parent = Page.manager.get(pk=10) # get object you want to get the children of
children = parent.get_children() # returns empty dict if no children are found

parent = children[0].get_parent() # gets the parent

Preordered trees are great if done correctly, this is not.