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.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.

Installation

Install using pip

$ pip install django-polymorphic

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-1.1b2.tar.gz (99.1 kB view details)

Uploaded Source

Built Distribution

django_polymorphic-1.1b2-py2.py3-none-any.whl (77.9 kB view details)

Uploaded Python 2 Python 3

File details

Details for the file django-polymorphic-1.1b2.tar.gz.

File metadata

File hashes

Hashes for django-polymorphic-1.1b2.tar.gz
Algorithm Hash digest
SHA256 f2facda7204ec93a6482ee1d39b6611f88fe2290b383b37857df8be5c3f34f34
MD5 9bcac354f61240e278f46bde7de690f2
BLAKE2b-256 f163ad930026037b7b757e54687c21a7cdaea62cfc67ac87fad71d8665a51981

See more details on using hashes here.

Provenance

File details

Details for the file django_polymorphic-1.1b2-py2.py3-none-any.whl.

File metadata

File hashes

Hashes for django_polymorphic-1.1b2-py2.py3-none-any.whl
Algorithm Hash digest
SHA256 417a3d7de30c7280647ebd71317b3a5df95f1baa7074d009a38da7f6a4ed1ec0
MD5 f2da7fb6a2405ceec9e2fbef05f5790c
BLAKE2b-256 c037796ebfab8501c8b838ea1de6b5ee85b84e7d4a3ba664e03401f3a5c4099a

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