diff options
Diffstat (limited to 'docs')
| -rw-r--r-- | docs/ref/models/fields.txt | 30 |
1 files changed, 20 insertions, 10 deletions
diff --git a/docs/ref/models/fields.txt b/docs/ref/models/fields.txt index 2ec74e4306..177df12862 100644 --- a/docs/ref/models/fields.txt +++ b/docs/ref/models/fields.txt @@ -800,21 +800,22 @@ you can use the name of the model, rather than the model object itself:: class Manufacturer(models.Model): # ... -Note, however, that this only refers to models in the same ``models.py`` file -- -you cannot use a string to reference a model defined in another application or -imported from elsewhere. - -.. versionchanged:: 1.0 - Refering models in other applications must include the application label. +.. versionadded:: 1.0 -To refer to models defined in another -application, you must instead explicitly specify the application label. For -example, if the ``Manufacturer`` model above is defined in another application -called ``production``, you'd need to use:: +To refer to models defined in another application, you can explicitly specify +a model with the full application label. For example, if the ``Manufacturer`` +model above is defined in another application called ``production``, you'd +need to use:: class Car(models.Model): manufacturer = models.ForeignKey('production.Manufacturer') +This sort of reference can be useful when resolving circular import +dependencies between two applications. + +Database Representation +~~~~~~~~~~~~~~~~~~~~~~~ + Behind the scenes, Django appends ``"_id"`` to the field name to create its database column name. In the above example, the database table for the ``Car`` model will have a ``manufacturer_id`` column. (You can change this explicitly by @@ -824,6 +825,9 @@ deal with the field names of your model object. .. _foreign-key-arguments: +Arguments +~~~~~~~~~ + :class:`ForeignKey` accepts an extra set of arguments -- all optional -- that define the details of how the relation works. @@ -871,6 +875,9 @@ the model is related. This works exactly the same as it does for :class:`ForeignKey`, including all the options regarding :ref:`recursive <recursive-relationships>` and :ref:`lazy <lazy-relationships>` relationships. +Database Representation +~~~~~~~~~~~~~~~~~~~~~~~ + Behind the scenes, Django creates an intermediary join table to represent the many-to-many relationship. By default, this table name is generated using the names of the two tables being joined. Since some databases don't support table @@ -882,6 +889,9 @@ You can manually provide the name of the join table using the .. _manytomany-arguments: +Arguments +~~~~~~~~~ + :class:`ManyToManyField` accepts an extra set of arguments -- all optional -- that control how the relationship functions. |