I read a lot about nested sets and materialized path, a few years ago I used nested sets with phpdoctrine ( http://www.doctrine-project.org/documentation/manual/1_2/nl/hierarchical-data ) but I didn't see that before, thank you very much for sharing!
seems close to what I do, but still there are differences: - I have an 'optimization' field: precomputed field 'num_children' - 'line' is the order of the record in the table, not the order of the child (make sense? ...) - he uses joins to retrieve subtrees, but I also want it to run on GAE, which doesn't (yet) support joins, and support comparison operations only on one field, I don;t have at the moment speed comparison between different implementations, but I will definitely test against nested sets, and to this model implementation thank you again for sharing, I need this kind of links, to know my model 'rivals', to study their strengths and weaknesses :)
