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Doc'd that model instances with pk=None don't compare equal.

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Adam Chainz 2016-10-07 10:40:16 +01:00 committed by Tim Graham
parent 0a26f3c338
commit 224fe22bf1
1 changed files with 14 additions and 5 deletions
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19
docs/ref/models/instances.txt
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@ -638,9 +638,10 @@ with :func:`~django.utils.encoding.python_2_unicode_compatible` as shown above.
.. method:: Model.__eq__()
The equality method is defined such that instances with the same primary
key value and the same concrete class are considered equal. For proxy
models, concrete class is defined as the model's first non-proxy parent;
for all other models it is simply the model's class.
key value and the same concrete class are considered equal, except that
instances with a primary key value of ``None`` aren't equal to anything except
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::
@ -656,10 +657,18 @@ For example::
class MultitableInherited(MyModel):
pass
# Primary keys compared
MyModel(id=1) == MyModel(id=1)
MyModel(id=1) == MyProxyModel(id=1)
MyModel(id=1) != MultitableInherited(id=1)
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__()``
--------------