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Storing hierarchical (parent/child) data in Python/Django: MPTT alternative?

I'm looking for a good way to store and use hierarchical (parent/child) data in Django. I've been using django-mptt, but it seems entirely incompatible with my brain - I end up with non-obvious bugs in non-obvious places, mostly when moving things around in the tree: I end up with inconsistent state, where a node and its parent will disagree on their relationship.

My needs are simple:

  • Given a node:
    • find its root
    • find its ancestors
    • find its descendants
  • With a tree:
    • easily move nodes (ie. change parent)

My trees will be smallish (at most 10k nodes over 20 levels, generally much much smaller, say 10 nodes with 1 or 2 levels).

I have to think there has to be an easier way to do trees in python/django. Are there other approaches that do a better job of maintaining consistency?

like image 949
Parand Avatar asked Apr 23 '10 15:04

Parand


1 Answers

django-treebeard is another option. It has great documentation. I believe it meets all of your above requirements and includes some functions for checking the tree for problems and fixing those problems in the tree.

Node.find_problems() https://tabo.pe/projects/django-treebeard/docs/1.60/api.html#treebeard.models.Node.find_problems

Node.fix_tree() https://tabo.pe/projects/django-treebeard/docs/1.60/api.html#treebeard.models.Node.fix_tree

like image 97
Mark Lavin Avatar answered Oct 18 '22 08:10

Mark Lavin