56 lines
2.1 KiB
ReStructuredText
56 lines
2.1 KiB
ReStructuredText
**2010-1-26**
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IMPORTANT - database schema change (more info in change log).
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I hope I got this change in early enough before anyone started to use
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polymorphic.py in earnest. Sorry for any inconvenience.
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This should be the final DB schema now.
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Usage, Examples, Installation & Documentation, Links
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----------------------------------------------------
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* Documentation_ and Overview_
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* `Discussion, Questions, Suggestions`_
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* GitHub_ - Bitbucket_ - `Download as TGZ`_ or ZIP_
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.. _Documentation: http://bserve.webhop.org/wiki/django_polymorphic/doc
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.. _Discussion, Questions, Suggestions: http://django-polymorphic.blogspot.com/2010/01/messages.html
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.. _GitHub: http://github.com/bconstantin/django_polymorphic
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.. _Bitbucket: http://bitbucket.org/bconstantin/django_polymorphic
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.. _Download as TGZ: http://github.com/bconstantin/django_polymorphic/tarball/master
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.. _ZIP: http://github.com/bconstantin/django_polymorphic/zipball/master
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.. _Overview: http://bserve.webhop.org/wiki/django_polymorphic
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What is django_polymorphic good for?
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------------------------------------
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If ``ArtProject`` and ``ResearchProject`` inherit from the model ``Project``:
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>>> Project.objects.all()
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.
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[ <Project: id 1, topic: "John's Gathering">,
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<ArtProject: id 2, topic: "Sculpting with Tim", artist: "T. Turner">,
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<ResearchProject: id 3, topic: "Swallow Aerodynamics", supervisor: "Dr. Winter"> ]
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In general, objects retrieved from the database are always returned back
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with the same type/class and fields they were created and saved with.
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It doesn't matter how these objects are retrieved: be it through the
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model's own managers/querysets, ForeignKeys, ManyToManyFields
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or OneToOneFields.
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The resulting querysets are polymorphic, i.e they may deliver
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objects of several different types in a single query result.
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``django_polymorphic`` consists of just one add-on module, ``polymorphic.py``,
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that adds this functionality to Django's model inheritance system
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(for models that request this behaviour).
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Status
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------
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This module is still very experimental. Please see the docs for current restrictions,
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caveats, and performance implications.
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