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Code Issues 32 Releases Wiki Activity

[1.10.x] Doc'd that model instances with pk=None don't compare equal.

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Backport of 224fe22bf1628c1feff110ce993dcb33880bf3a3 from master
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Adam Chainz 2016-10-07 10:40:16 +01:00 committed by Tim Graham
parent c2853807bc
commit 27d352800c
1 changed files with 14 additions and 5 deletions
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docs/ref/models/instances.txt
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@ -646,9 +646,10 @@ with :func:`~django.utils.encoding.python_2_unicode_compatible` as shown above.
.. method:: Model.__eq__() .. method:: Model.__eq__()
The equality method is defined such that instances with the same primary The equality method is defined such that instances with the same primary
key value and the same concrete class are considered equal. For proxy key value and the same concrete class are considered equal, except that
models, concrete class is defined as the model's first non-proxy parent; instances with a primary key value of ``None`` aren't equal to anything except
for all other models it is simply the model's class. themselves. For proxy models, concrete class is defined as the model's first
non-proxy parent; for all other models it's simply the model's class.
For example:: For example::
@ -664,10 +665,18 @@ For example::
class MultitableInherited(MyModel): class MultitableInherited(MyModel):
pass pass
# Primary keys compared
MyModel(id=1) == MyModel(id=1) MyModel(id=1) == MyModel(id=1)
MyModel(id=1) == MyProxyModel(id=1)
MyModel(id=1) != MultitableInherited(id=1)
MyModel(id=1) != MyModel(id=2) MyModel(id=1) != MyModel(id=2)
# Primay keys are None
MyModel(id=None) != MyModel(id=None)
# Same instance
instance = MyModel(id=None)
instance == instance
# Proxy model
MyModel(id=1) == MyProxyModel(id=1)
# Multi-table inheritance
MyModel(id=1) != MultitableInherited(id=1)
``__hash__()`` ``__hash__()``
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