Fixed #10981 -- Clarified documentation regarding lazy cross-application relationships. Thanks to Ramiro for the suggestion.
git-svn-id: http://code.djangoproject.com/svn/django/trunk@10971 bcc190cf-cafb-0310-a4f2-bffc1f526a37
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@ -800,21 +800,22 @@ you can use the name of the model, rather than the model object itself::
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class Manufacturer(models.Model):
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# ...
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Note, however, that this only refers to models in the same ``models.py`` file --
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you cannot use a string to reference a model defined in another application or
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imported from elsewhere.
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.. versionadded:: 1.0
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.. versionchanged:: 1.0
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Refering models in other applications must include the application label.
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To refer to models defined in another
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application, you must instead explicitly specify the application label. For
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example, if the ``Manufacturer`` model above is defined in another application
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called ``production``, you'd need to use::
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To refer to models defined in another application, you can explicitly specify
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a model with the full application label. For example, if the ``Manufacturer``
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model above is defined in another application called ``production``, you'd
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need to use::
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class Car(models.Model):
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manufacturer = models.ForeignKey('production.Manufacturer')
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This sort of reference can be useful when resolving circular import
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dependencies between two applications.
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Database Representation
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~~~~~~~~~~~~~~~~~~~~~~~
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Behind the scenes, Django appends ``"_id"`` to the field name to create its
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database column name. In the above example, the database table for the ``Car``
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model will have a ``manufacturer_id`` column. (You can change this explicitly by
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@ -824,6 +825,9 @@ deal with the field names of your model object.
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.. _foreign-key-arguments:
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Arguments
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~~~~~~~~~
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:class:`ForeignKey` accepts an extra set of arguments -- all optional -- that
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define the details of how the relation works.
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@ -871,6 +875,9 @@ the model is related. This works exactly the same as it does for
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:class:`ForeignKey`, including all the options regarding :ref:`recursive
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<recursive-relationships>` and :ref:`lazy <lazy-relationships>` relationships.
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Database Representation
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~~~~~~~~~~~~~~~~~~~~~~~
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Behind the scenes, Django creates an intermediary join table to represent the
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many-to-many relationship. By default, this table name is generated using the
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names of the two tables being joined. Since some databases don't support table
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@ -882,6 +889,9 @@ You can manually provide the name of the join table using the
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.. _manytomany-arguments:
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Arguments
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~~~~~~~~~
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:class:`ManyToManyField` accepts an extra set of arguments -- all optional --
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that control how the relationship functions.
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