Added `using` to the list of documented arguments for save() on a model; updated the docs to suggest using ``*args, **kwargs`` when implementing model save methods. Thanks to Jeff Croft for the report.
git-svn-id: http://code.djangoproject.com/svn/django/trunk@12118 bcc190cf-cafb-0310-a4f2-bffc1f526a37
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@ -66,15 +66,20 @@ Saving objects
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To save an object back to the database, call ``save()``:
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.. method:: Model.save([force_insert=False, force_update=False])
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Of course, there are some subtleties; see the sections below.
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.. method:: Model.save([force_insert=False, force_update=False, using=DEFAULT_DB_ALIAS])
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.. versionadded:: 1.0
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The ``force_insert`` and ``force_update`` arguments were added.
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The signature of the ``save()`` method has changed from earlier versions
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(``force_insert`` and ``force_update`` have been added). If you are overriding
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these methods, be sure to use the correct signature.
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.. versionadded:: 1.1
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The ``using`` argument was added.
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If you want customized saving behavior, you can override this
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``save()`` method. See :ref:`overriding-model-methods` for more
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details.
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The model save process also has some subtleties; see the sections
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below.
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Auto-incrementing primary keys
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------------------------------
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@ -265,14 +270,21 @@ For more details, see the documentation on :ref:`F() expressions
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Deleting objects
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================
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.. method:: Model.delete()
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.. method:: Model.delete([using=DEFAULT_DB_ALIAS])
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Issues a SQL ``DELETE`` for the object. This only deletes the object in the
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database; the Python instance will still be around, and will still have data
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in its fields.
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.. versionadded:: 1.1
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The ``using`` argument was added.
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For more details, including how to delete objects in bulk, see
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:ref:`topics-db-queries-delete`.
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Issues a SQL ``DELETE`` for the object. This only deletes the object
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in the database; the Python instance will still be around, and will
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still have data in its fields.
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For more details, including how to delete objects in bulk, see
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:ref:`topics-db-queries-delete`.
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If you want customized deletion behavior, you can override this
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``delete()`` method. See :ref:`overriding-model-methods` for more
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details.
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.. _model-instance-methods:
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@ -707,6 +707,8 @@ below -- but there are a couple that you'll almost always want to define:
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Any object that has a URL that uniquely identifies it should define this
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method.
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.. _overriding-model-methods:
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Overriding predefined model methods
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-----------------------------------
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@ -726,9 +728,9 @@ to happen whenever you save an object. For example (see
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name = models.CharField(max_length=100)
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tagline = models.TextField()
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def save(self, force_insert=False, force_update=False):
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def save(self, *args, **kwargs):
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do_something()
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super(Blog, self).save(force_insert, force_update) # Call the "real" save() method.
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super(Blog, self).save(*args, **kwargs) # Call the "real" save() method.
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do_something_else()
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You can also prevent saving::
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@ -737,16 +739,24 @@ You can also prevent saving::
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name = models.CharField(max_length=100)
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tagline = models.TextField()
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def save(self, force_insert=False, force_update=False):
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def save(self, *args, **kwargs):
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if self.name == "Yoko Ono's blog":
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return # Yoko shall never have her own blog!
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else:
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super(Blog, self).save(force_insert, force_update) # Call the "real" save() method.
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super(Blog, self).save(*args, **kwargs) # Call the "real" save() method.
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It's important to remember to call the superclass method -- that's that
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``super(Blog, self).save()`` business -- to ensure that the object still gets
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saved into the database. If you forget to call the superclass method, the
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default behavior won't happen and the database won't get touched.
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It's important to remember to call the superclass method -- that's
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that ``super(Blog, self).save(*args, **kwargs)`` business -- to ensure
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that the object still gets saved into the database. If you forget to
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call the superclass method, the default behavior won't happen and the
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database won't get touched.
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It's also important that you pass through the arguments that can be
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passed to the model method -- that's what the ``*args, **kwargs`` bit
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does. Django will, from time to time, extend the capabilities of
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built-in model methods, adding new arguments. If you use ``*args,
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**kwargs`` in your method definitions, you are guaranteed that your
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code will automatically support those arguments when they are added.
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Executing custom SQL
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--------------------
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