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Diffstat (limited to 'docs/ref')
| -rw-r--r-- | docs/ref/models/instances.txt | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/docs/ref/models/instances.txt b/docs/ref/models/instances.txt index 6295eb0407..da657a9a01 100644 --- a/docs/ref/models/instances.txt +++ b/docs/ref/models/instances.txt @@ -521,6 +521,25 @@ For example:: In previous versions only instances of the exact same class and same primary key value were considered equal. +``__hash__`` +------------ + +.. method:: Model.__hash__() + +The ``__hash__`` method is based on the instance's primary key value. It +is effectively hash(obj.pk). If the instance doesn't have a primary key +value then a ``TypeError`` will be raised (otherwise the ``__hash__`` +method would return different values before and after the instance is +saved, but changing the ``__hash__`` value of an instance `is forbidden +in Python`_). + +.. versionchanged:: 1.7 + + In previous versions instance's without primary key value were + hashable. + +.. _is forbidden in Python: http://docs.python.org/reference/datamodel.html#object.__hash__ + ``get_absolute_url`` -------------------- |