Skip to main content

Seamless Polymorphic Inheritance for Django Models

Project description

https://travis-ci.org/django-polymorphic/django-polymorphic.png?branch=master https://img.shields.io/pypi/v/django-polymorphic-tree.svg https://img.shields.io/codecov/c/github/django-polymorphic/django-polymorphic/master.svg

Polymorphic Models for Django

Django-polymorphic simplifies using inherited models in Django projects. When a query is made at the base model, the inherited model classes are returned.

When we store models that inherit from a Project model…

>>> Project.objects.create(topic="Department Party")
>>> ArtProject.objects.create(topic="Painting with Tim", artist="T. Turner")
>>> ResearchProject.objects.create(topic="Swallow Aerodynamics", supervisor="Dr. Winter")

…and want to retrieve all our projects, the subclassed models are returned!

>>> Project.objects.all()
[ <Project:         id 1, topic "Department Party">,
  <ArtProject:      id 2, topic "Painting with Tim", artist "T. Turner">,
  <ResearchProject: id 3, topic "Swallow Aerodynamics", supervisor "Dr. Winter"> ]

Using vanilla Django, we get the base class objects, which is rarely what we wanted:

>>> Project.objects.all()
[ <Project: id 1, topic "Department Party">,
  <Project: id 2, topic "Painting with Tim">,
  <Project: id 3, topic "Swallow Aerodynamics"> ]

This also works when the polymorphic model is accessed via ForeignKeys, ManyToManyFields or OneToOneFields.

Features

  • Full admin integration.

  • ORM integration:

  • support for ForeignKey, ManyToManyField, OneToOneField descriptors.

  • Filtering/ordering of inherited models (ArtProject___artist).

  • Filtering model types: instance_of(...) and not_instance_of(...)

  • Combining querysets of different models (qs3 = qs1 | qs2)

  • Support for custom user-defined managers.

  • Uses the minumum amount of queries needed to fetch the inherited models.

  • Disabling polymorphic behavior when needed.

While django-polymorphic makes subclassed models easy to use in Django, we still encourage to use them with caution. Each subclassed model will require Django to perform an INNER JOIN to fetch the model fields from the database. While taking this in mind, there are valid reasons for using subclassed models. That’s what this library is designed for!

For more information, see the documentation at Read the Docs.

License

Django-polymorphic uses the same license as Django (BSD-like).

Project details


Download files

Download the file for your platform. If you're not sure which to choose, learn more about installing packages.

Source Distribution

django-polymorphic-1.0b1.tar.gz (56.4 kB view details)

Uploaded Source

Built Distribution

django_polymorphic-1.0b1-py2.py3-none-any.whl (63.8 kB view details)

Uploaded Python 2 Python 3

File details

Details for the file django-polymorphic-1.0b1.tar.gz.

File metadata

File hashes

Hashes for django-polymorphic-1.0b1.tar.gz
Algorithm Hash digest
SHA256 fdce261ab0b4fa85513c09e969b7e97d8766b6dfda50a41984a1da6b52ae925c
MD5 f3053c7bdc081ac10a59ce8bad6e301f
BLAKE2b-256 d6643f546843bde819b420015b3fc00a5a20afc612b4fd53d0839655ca704d5a

See more details on using hashes here.

Provenance

File details

Details for the file django_polymorphic-1.0b1-py2.py3-none-any.whl.

File metadata

File hashes

Hashes for django_polymorphic-1.0b1-py2.py3-none-any.whl
Algorithm Hash digest
SHA256 eedfbab58a51a371355f129e7a72a5fec97eb15bedbe98a310c419756876d2e7
MD5 185c42101edbaeeec378f7dbeb67505d
BLAKE2b-256 08c615c5327e5f3ac9d4f38a308a3d53fde85c66c637de51ac3bed3de7b493bd

See more details on using hashes here.

Provenance

Supported by

AWS AWS Cloud computing and Security Sponsor Datadog Datadog Monitoring Fastly Fastly CDN Google Google Download Analytics Microsoft Microsoft PSF Sponsor Pingdom Pingdom Monitoring Sentry Sentry Error logging StatusPage StatusPage Status page