Merge pull request #1567 from technivore/ticket_20970

re-indented method documentation within RelatedManager
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Tim Graham 2013-09-06 12:07:25 -07:00
commit 38d2e7c225
1 changed files with 70 additions and 75 deletions

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@ -36,104 +36,99 @@ Related objects reference
In this example, the methods below will be available both on In this example, the methods below will be available both on
``topping.pizza_set`` and on ``pizza.toppings``. ``topping.pizza_set`` and on ``pizza.toppings``.
.. _related-manager-methods: .. method:: add(obj1, [obj2, ...])
Related Manager Methods Adds the specified model objects to the related object set.
-----------------------
.. method:: add(obj1, [obj2, ...]) Example::
Adds the specified model objects to the related object set. >>> b = Blog.objects.get(id=1)
>>> e = Entry.objects.get(id=234)
>>> b.entry_set.add(e) # Associates Entry e with Blog b.
Example:: In the example above, in the case of a
:class:`~django.db.models.ForeignKey` relationship,
``e.save()`` is called by the related manager to perform the update.
Using ``add()`` with a many-to-many relationship, however, will not
call any ``save()`` methods, but rather create the relationships
using :meth:`QuerySet.bulk_create()
<django.db.models.query.QuerySet.bulk_create>`. If you need to execute
some custom logic when a relationship is created, listen to the
:data:`~django.db.models.signals.m2m_changed` signal.
>>> b = Blog.objects.get(id=1) .. method:: create(**kwargs)
>>> e = Entry.objects.get(id=234)
>>> b.entry_set.add(e) # Associates Entry e with Blog b.
In the example above, in the case of a Creates a new object, saves it and puts it in the related object set.
:class:`~django.db.models.ForeignKey` relationship, Returns the newly created object::
``e.save()`` is called by the related manager to perform the update.
Using ``add()`` with a many-to-many relationship, however, will not
call any ``save()`` methods, but rather create the relationships
using :meth:`QuerySet.bulk_create()
<django.db.models.query.QuerySet.bulk_create>`. If you need to execute
some custom logic when a relationship is created, listen to the
:data:`~django.db.models.signals.m2m_changed` signal.
.. method:: create(**kwargs) >>> b = Blog.objects.get(id=1)
>>> e = b.entry_set.create(
... headline='Hello',
... body_text='Hi',
... pub_date=datetime.date(2005, 1, 1)
... )
Creates a new object, saves it and puts it in the related object set. # No need to call e.save() at this point -- it's already been saved.
Returns the newly created object::
>>> b = Blog.objects.get(id=1) This is equivalent to (but much simpler than)::
>>> e = b.entry_set.create(
... headline='Hello',
... body_text='Hi',
... pub_date=datetime.date(2005, 1, 1)
... )
# No need to call e.save() at this point -- it's already been saved. >>> b = Blog.objects.get(id=1)
>>> e = Entry(
... blog=b,
... headline='Hello',
... body_text='Hi',
... pub_date=datetime.date(2005, 1, 1)
... )
>>> e.save(force_insert=True)
This is equivalent to (but much simpler than):: Note that there's no need to specify the keyword argument of the model
that defines the relationship. In the above example, we don't pass the
parameter ``blog`` to ``create()``. Django figures out that the new
``Entry`` object's ``blog`` field should be set to ``b``.
>>> b = Blog.objects.get(id=1) .. method:: remove(obj1, [obj2, ...])
>>> e = Entry(
... blog=b,
... headline='Hello',
... body_text='Hi',
... pub_date=datetime.date(2005, 1, 1)
... )
>>> e.save(force_insert=True)
Note that there's no need to specify the keyword argument of the model Removes the specified model objects from the related object set::
that defines the relationship. In the above example, we don't pass the
parameter ``blog`` to ``create()``. Django figures out that the new
``Entry`` object's ``blog`` field should be set to ``b``.
.. method:: remove(obj1, [obj2, ...]) >>> b = Blog.objects.get(id=1)
>>> e = Entry.objects.get(id=234)
>>> b.entry_set.remove(e) # Disassociates Entry e from Blog b.
Removes the specified model objects from the related object set:: Similar to :meth:`add()`, ``e.save()`` is called in the example above
to perform the update. Using ``remove()`` with a many-to-many
relationship, however, will delete the relationships using
:meth:`QuerySet.delete()<django.db.models.query.QuerySet.delete>` which
means no model ``save()`` methods are called; listen to the
:data:`~django.db.models.signals.m2m_changed` signal if you wish to
execute custom code when a relationship is deleted.
>>> b = Blog.objects.get(id=1) For :class:`~django.db.models.ForeignKey` objects, this method only
>>> e = Entry.objects.get(id=234) exists if ``null=True``. If the related field can't be set to ``None``
>>> b.entry_set.remove(e) # Disassociates Entry e from Blog b. (``NULL``), then an object can't be removed from a relation without
being added to another. In the above example, removing ``e`` from
``b.entry_set()`` is equivalent to doing ``e.blog = None``, and because
the ``blog`` :class:`~django.db.models.ForeignKey` doesn't have
``null=True``, this is invalid.
Similar to :meth:`add()`, ``e.save()`` is called in the example above .. method:: clear()
to perform the update. Using ``remove()`` with a many-to-many
relationship, however, will delete the relationships using
:meth:`QuerySet.delete()<django.db.models.query.QuerySet.delete>` which
means no model ``save()`` methods are called; listen to the
:data:`~django.db.models.signals.m2m_changed` signal if you wish to
execute custom code when a relationship is deleted.
For :class:`~django.db.models.ForeignKey` objects, this method only Removes all objects from the related object set::
exists if ``null=True``. If the related field can't be set to ``None``
(``NULL``), then an object can't be removed from a relation without
being added to another. In the above example, removing ``e`` from
``b.entry_set()`` is equivalent to doing ``e.blog = None``, and because
the ``blog`` :class:`~django.db.models.ForeignKey` doesn't have
``null=True``, this is invalid.
.. method:: clear() >>> b = Blog.objects.get(id=1)
>>> b.entry_set.clear()
Removes all objects from the related object set:: Note this doesn't delete the related objects -- it just disassociates
them.
>>> b = Blog.objects.get(id=1) Just like ``remove()``, ``clear()`` is only available on
>>> b.entry_set.clear() :class:`~django.db.models.ForeignKey`\s where ``null=True``.
Note this doesn't delete the related objects -- it just disassociates .. note::
them.
Just like ``remove()``, ``clear()`` is only available on Note that ``add()``, ``create()``, ``remove()``, and ``clear()`` all
:class:`~django.db.models.ForeignKey`\s where ``null=True``. 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
.. note:: relationship.
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.
.. _direct-assignment: .. _direct-assignment: