Skip to main content

Seamless Polymorphic Inheritance for Django Models

Project description

https://travis-ci.org/django-polymorphic/django-polymorphic.svg?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!

The current release of django-polymorphic supports Django 1.8, 1.10, 1.11 and Python 2.7 and 3.4+ is supported. For older Django versions, install django-polymorphic==1.2.

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-1.3.tar.gz (96.8 kB view details)

Uploaded Source

Built Distribution

django_polymorphic-1.3-py2.py3-none-any.whl (75.2 kB view details)

Uploaded Python 2 Python 3

File details

Details for the file django-polymorphic-1.3.tar.gz.

File metadata

File hashes

Hashes for django-polymorphic-1.3.tar.gz
Algorithm Hash digest
SHA256 8737b465ebf5fad772b4c52272189c352f5904f468d298584a3469187e3207ad
MD5 017a1534f091fb2a8ca9eb9ec5f211f9
BLAKE2b-256 da8d8efc291508c3c5e8051b690b5b15f5b624c6449df5335b7316e8154e947d

See more details on using hashes here.

Provenance

File details

Details for the file django_polymorphic-1.3-py2.py3-none-any.whl.

File metadata

File hashes

Hashes for django_polymorphic-1.3-py2.py3-none-any.whl
Algorithm Hash digest
SHA256 8f4e36ada0ec16b98de0b6e53477772fcac3ece89a1da8473ee6aa4e658775a7
MD5 d57c7cfc28f06930b674945f5e8afea8
BLAKE2b-256 8f2fa13bcaf1d098b111e53460798f37270107143c2ac1a2ce5800b37e1dfb79

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