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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...
.. code-block:: python
>>> 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!
.. code-block:: python
>>> 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:
.. code-block:: python
>>> 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
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 2.1, 2.2, 3.0, 3.1
and Python 3.5+ is supported.
For older Django versions, install django-polymorphic==1.3.
For more information, see the documentation at Read the Docs <https://django-polymorphic.readthedocs.io/>
_.
Installation
Install using pip
\ ...
.. code:: bash
$ pip install django-polymorphic
License
Django-polymorphic uses the same license as Django (BSD-like).