django-polymorphic

django-polymorphic builds on top of the standard Django model inheritance. It makes using inherited models easier. 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"> ]

Features

  • Full admin integration.

  • ORM integration:

    • Support for ForeignKey, ManyToManyField, OneToOneField descriptors.

    • Support for proxy models.

    • 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.

  • Formset support.

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

  • Disabling polymorphic behavior when needed.

Getting started

Advanced topics

Indices and tables