A TreeForeignKey is just a regular ForeignKey that renders form fields differently in the admin and a few other places. Because you’re inheriting from MPTTModel, your model will also have a number of other fields: level, lft, rght, and tree_id.
What is mptt and how does it work?
MPTT is a technique for storing hierarchical data in a database. The aim is to make retrieval operations very efficient. The trade-off for this efficiency is that performing inserts and moving items around the tree is more involved, as there’s some extra work required to keep the tree structure in a good state at all times.
What is modified preorder tree traversal in Django?
Utilities for implementing Modified Preorder Tree Traversal with your Django Models and working with trees of Model instances. What is Modified Preorder Tree Traversal? MPTT is a technique for storing hierarchical data in a database. The aim is to make retrieval operations very efficient.
What fields should I expect to see in my mptt model?
Because you’re inheriting from MPTTModel, your model will also have a number of other fields: level, lft, rght, and tree_id. These fields are managed by the MPTT algorithm. Most of the time you won’t need to use these fields directly.
How do I change the name of a field in mpttmeta?
To change the names, create an MPTTMeta class inside your class: The available options for the MPTTMeta class are: The name of a field which relates the model back to itself such that each instance can be a child of another instance. Defaults to ‘parent’.
How do I reverse the Order of ancestors in mpttmodel?
Subclasses of MPTTModel have the following instance methods: Creates a QuerySet containing the ancestors of the model instance. These default to being in descending order (root ancestor first, immediate parent last); passing True for the ascending argument will reverse the ordering (immediate parent first, root ancestor last).
