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Code Issues 32 Releases Wiki Activity

Fixed #6707 -- Added RelatedManager.set() and made descriptors' __set__ use it.

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Thanks Anssi Kääriäinen, Carl Meyer, Collin Anderson, and Tim Graham for the reviews.
This commit is contained in:
Loic Bistuer
2015-01-30 01:15:27 +07:00
parent 49516f7158
commit 71ada3a8e6
10 changed files with 350 additions and 100 deletions
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39
docs/ref/models/relations.txt
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@@ -135,12 +135,31 @@ Related objects reference
:class:`~django.db.models.ForeignKey`\s where ``null=True`` and it also
accepts the ``bulk`` keyword argument.
.. method:: set(objs, clear=False)
.. versionadded:: 1.9
Replace the set of related objects::
>>> new_list = [obj1, obj2, obj3]
>>> e.related_set.set(new_list)
This method accepts a ``clear`` argument to control how to perform the
operation. If ``False`` (the default), the elements missing from the
new set are removed using ``remove()`` and only the new ones are added.
If ``clear=True``, the ``clear()`` method is called instead and the
whole set is added at once.
Note that since ``set()`` is a compound operation, it is subject to
race conditions. For instance, new objects may be added to the database
in between the call to ``clear()`` and the call to ``add()``.
.. note::
Note that ``add()``, ``create()``, ``remove()``, and ``clear()`` all
apply database changes immediately for all types of related fields. In
other words, there is no need to call ``save()`` on either end of the
relationship.
Note that ``add()``, ``create()``, ``remove()``, ``clear()``, and
``set()`` all apply database changes immediately for all types of
related fields. In other words, there is no need to call ``save()``
on either end of the relationship.
Also, if you are using :ref:`an intermediate model
<intermediary-manytomany>` for a many-to-many relationship, some of the
@@ -158,6 +177,12 @@ new iterable of objects to it::
>>> e.related_set = new_list
If the foreign key relationship has ``null=True``, then the related manager
will first call ``clear()`` to disassociate any existing objects in the related
set before adding the contents of ``new_list``. Otherwise the objects in
``new_list`` will be added to the existing related object set.
will first disassociate any existing objects in the related set before adding
the contents of ``new_list``. Otherwise the objects in ``new_list`` will be
added to the existing related object set.
.. versionchanged:1.9
In earlier versions, direct assignment used to perform ``clear()`` followed
by ``add()``. It now performs a ``set()`` with the keyword argument
``clear=False``.