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Diffstat (limited to 'parts/django/docs/ref/models/relations.txt')
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diff --git a/parts/django/docs/ref/models/relations.txt b/parts/django/docs/ref/models/relations.txt deleted file mode 100644 index ee6bcdd..0000000 --- a/parts/django/docs/ref/models/relations.txt +++ /dev/null @@ -1,105 +0,0 @@ -========================= -Related objects reference -========================= - -.. currentmodule:: django.db.models.fields.related - -.. class:: RelatedManager - - A "related manager" is a manager used in a one-to-many or many-to-many - related context. This happens in two cases: - - * The "other side" of a :class:`~django.db.models.ForeignKey` relation. - That is:: - - class Reporter(models.Model): - ... - - class Article(models.Model): - reporter = models.ForeignKey(Reporter) - - In the above example, the methods below will be available on - the manager ``reporter.article_set``. - - * Both sides of a :class:`~django.db.models.ManyToManyField` relation:: - - class Topping(models.Model): - ... - - class Pizza(models.Model): - toppings = models.ManyToManyField(Topping) - - In this example, the methods below will be available both on - ``topping.pizza_set`` and on ``pizza.toppings``. - - These related managers have some extra methods: - - .. method:: add(obj1, [obj2, ...]) - - Adds the specified model objects to the related object set. - - Example:: - - >>> b = Blog.objects.get(id=1) - >>> e = Entry.objects.get(id=234) - >>> b.entry_set.add(e) # Associates Entry e with Blog b. - - .. method:: create(**kwargs) - - Creates a new object, saves it and puts it in the related object set. - Returns the newly created object:: - - >>> b = Blog.objects.get(id=1) - >>> 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. - - This is equivalent to (but much simpler than):: - - >>> 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) - - 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``. - - .. method:: remove(obj1, [obj2, ...]) - - Removes the specified model objects from the related object set:: - - >>> b = Blog.objects.get(id=1) - >>> e = Entry.objects.get(id=234) - >>> b.entry_set.remove(e) # Disassociates Entry e from Blog b. - - In order to prevent database inconsistency, this method only exists on - :class:`~django.db.models.ForeignKey` objects where ``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() - - Removes all objects from the related object set:: - - >>> b = Blog.objects.get(id=1) - >>> b.entry_set.clear() - - Note this doesn't delete the related objects -- it just disassociates - them. - - Just like ``remove()``, ``clear()`` is only available on - :class:`~django.db.models.ForeignKey`\s where ``null=True``. |