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Improved the docs even more.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@8864 bcc190cf-cafb-0310-a4f2-bffc1f526a37
This commit is contained in:
Brian Rosner 2008-09-02 17:57:18 +00:00
parent 7163fe4d96
commit a658d45a6c

View File

@ -387,15 +387,16 @@ tricky with subclassing.
Model Formsets
==============
Similar to regular formsets there are a couple enhanced formset classes that
provide all the right things to work with your models. Lets reuse the
``Author`` model from above::
Similar to :ref:`regular formsets <topics-forms-formsets>` there are a couple
enhanced formset classes that provide all the right things to work with your
models. Lets reuse the ``Author`` model from above::
>>> from django.forms.models import modelformset_factory
>>> AuthorFormSet = modelformset_factory(Author)
This will create a formset that is capable of working with the data associated
to the ``Author`` model. It works just like a regular formset::
to the ``Author`` model. It works just like a regular formset just that we are
working with ``ModelForm`` instances instead of ``Form`` instances::
>>> formset = AuthorFormSet()
>>> print formset
@ -435,6 +436,23 @@ be used as a base::
>>> AuthorFormSet = modelformset_factory(Author, formset=BaseAuthorFormSet)
Controlling which fields are used with ``fields`` and ``exclude``
-----------------------------------------------------------------
By default a model formset will use all fields in the model that are not marked
with ``editable=False``. However, this can be overidden at the formset level::
>>> AuthorFormSet = modelformset_factory(Author, fields=('name', 'title'))
Using ``fields`` will restrict the formset to use just the given fields. Or if
you need to go the other way::
>>> AuthorFormSet = modelformset_factory(Author, exclude=('birth_date',))
Using ``exclude`` will prevent the given fields from being used in the formset.
.. _saving-objects-in-the-formset:
Saving objects in the formset
-----------------------------
@ -516,17 +534,43 @@ formset to a user to edit ``Author`` model instances::
As you can see the view is not drastically different than how to use a formset
in a view. The only difference is that we call ``formset.save()`` to save the
data into the database. This was describe above in :ref:`ref-saving-objects-in-the-formset`.
data into the database. This is described above in
:ref:`saving-objects-in-the-formset`.
Using ``inlineformset_factory``
-------------------------------
The ``inlineformset_factory`` is a helper to a common usage pattern of working
with related objects through a foreign key. Suppose you have two models
``Author`` and ``Book``. You want to create a formset that works with the
books of a specific author. Here is how you could accomplish this::
with related objects through a foreign key. It takes all the same options as
a ``modelformset_factory``. Suppose you have these two models::
class Author(models.Model):
name = models.CharField(max_length=100)
class Book(models.Model):
author = models.ForeignKey(Author)
title = models.CharField(max_length=100)
If you want to create a formset that allows you to edit books belonging to
some author you would do::
>>> from django.forms.models import inlineformset_factory
>>> BookFormSet = inlineformset_factory(Author, Book)
>>> author = Author.objects.get(name=u'Orson Scott Card')
>>> formset = BookFormSet(instance=author)
More than one foriegn key to the same model
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
If your model contains more than one foreign key to the same model you will
need to resolve the ambiguity manually using ``fk_name``. Given the following
model::
class Friendship(models.Model):
from_friend = models.ForeignKey(Friend)
to_friend = models.ForeignKey(Friend)
length_in_months = models.IntegerField()
To resolve this you can simply use ``fk_name`` to ``inlineformset_factory``::
>>> FrienshipFormSet = inlineformset_factory(Friend, Friendship, fk_name="from_friend")