**2010-1-26**
IMPORTANT - database schema change (more info in change log).
I hope I got this change in early enough before anyone started to use
polymorphic.py in earnest. Sorry for any inconvenience.
This should be the final DB schema now.
Usage, Examples, Installation & Documentation, Links
----------------------------------------------------
* Please see the `Documentation and Examples`_ (or the short `Overview`_)
* News & comments: `News, Comments, Questions & Discussion`_
* The code can be found on GitHub_ and Bitbucket_, or downloaded as TGZ_ or ZIP_
.. _Documentation and Examples: http://bserve.webhop.org/wiki/django_polymorphic/doc
.. _News, Comments, Questions & Discussion: http://groups.google.de/group/django-polymorphic/topics
.. _GitHub: http://github.com/bconstantin/django_polymorphic
.. _Bitbucket: http://bitbucket.org/bconstantin/django_polymorphic
.. _TGZ: http://github.com/bconstantin/django_polymorphic/tarball/master
.. _ZIP: http://github.com/bconstantin/django_polymorphic/zipball/master
.. _Overview: http://bserve.webhop.org/wiki/django_polymorphic
What is django_polymorphic good for?
------------------------------------
It causes objects being retrieved from the database to always be returned back
with the same type/class and fields they were created and saved with.
Example:
If the models ``ArtProject`` and ``ResearchProject`` inherit from the model ``Project``,
and we have saved one of each of them into the database, then we can do::
>>> Project.objects.all()
.
[ <Project: id 1, topic: "John's Gathering">,
<ArtProject: id 2, topic: "Sculpting with Tim", artist: "T. Turner">,
<ResearchProject: id 3, topic: "Swallow Aerodynamics", supervisor: "Dr. Winter"> ]
It doesn't matter how these objects are retrieved: be it through the
model's own managers/querysets, ForeignKeys, ManyToManyFields
or OneToOneFields.
``django_polymorphic`` does this only for models that explicitly request
this behaviour (and implicitely for their submodels).
The resulting querysets are polymorphic, i.e they may deliver
objects of several different types in a single query result.
Status
------
It's important to consider that this code is still very new and
experimental. Please see the docs for current restrictions, caveats,
and performance implications.
It does seem to work well for a number of people (including me), but
it's still very early and API changes, code reorganisations or further
schema changes are still a possibility.
Right now it's suitable only for the more enterprising early adopters.
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