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==========================================
**This project is currently unmaintained**
==========================================
Alternatives to django-mptt include:
* `django-treebeard `_ includes
a MPTT
implementation (called nested set), but the state of maintenance is
unclear.
* Maybe you do not need MPTT, especially when using newer databases. See
`django-tree-queries `_
for an
implementation using recursive Common Table Expressions (CTE). See the
[announcement blog post].
===========
django-mptt
===========
Utilities for implementing Modified Preorder Tree Traversal with your
Django Models and working with trees of Model instances.
Project home: https://github.com/django-mptt/django-mptt/
Documentation: https://django-mptt.readthedocs.io/
Discussion group: https://groups.google.com/forum/#!forum/django-mptt-dev
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.
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.
Here are a few articles about MPTT to whet your appetite and provide
details about how the technique itself works:
* `Trees in SQL`_
* `Storing Hierarchical Data in a Database`_
* `Managing Hierarchical Data in MySQL`_
.. _`Trees in SQL`:
https://www.ibase.ru/files/articles/programming/dbmstrees/sqltrees.html
.. _`Storing Hierarchical Data in a Database`:
https://www.sitepoint.com/hierarchical-data-database/
.. _`Managing Hierarchical Data in MySQL`:
http://mikehillyer.com/articles/managing-hierarchical-data-in-mysql/
What is ``django-mptt``?
========================
``django-mptt`` is a reusable Django app which aims to make it easy for you
to use MPTT with your own Django models.
It takes care of the details of managing a database table as a tree
structure and provides tools for working with trees of model instances.
Requirements
------------
* Python 3.6+
* A supported version of Django (currently 2.2+)
Feature overview
----------------
* Simple registration of models - fields required for tree structure will
be
added automatically.
* The tree structure is automatically updated when you create or delete
model instances, or change an instance's parent.
* Each level of the tree is automatically sorted by a field (or fields) of
your
choice.
* New model methods are added to each registered model for:
* changing position in the tree
* retrieving ancestors, siblings, descendants
* counting descendants
* other tree-related operations
* A TreeManager manager is added to all registered models. This provides
methods to:
* move nodes around a tree, or into a different tree
* insert a node anywhere in a tree
* rebuild the MPTT fields for the tree (useful when you do bulk updates
outside of django)
* `Form fields`_ for tree models.
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