Author: jacob Date: 2007-01-03 16:37:05 -0600 (Wed, 03 Jan 2007) New Revision: 4280
Modified: django/trunk/docs/db-api.txt django/trunk/docs/settings.txt Log: Fixed #3226: removed some pre-magic-removal-isms in settings docs. Thanks, ubernostrum. Modified: django/trunk/docs/db-api.txt =================================================================== --- django/trunk/docs/db-api.txt 2007-01-03 20:46:26 UTC (rev 4279) +++ django/trunk/docs/db-api.txt 2007-01-03 22:37:05 UTC (rev 4280) @@ -121,19 +121,37 @@ Saving changes to objects ========================= -To save changes to an object that's already in the database, use ``save()``. +``save()`` +---------- -Given a ``Blog`` instance ``b5`` that has already been saved to the database, -this example changes its name and updates its record in the database:: +Use the ``save()`` method to save an object to the database after making +changes to it:: - b5.name = 'New name' - b5.save() + newblog.name = "Brave New World" + newblog.save() -This performs an ``UPDATE`` SQL statement behind the scenes. Django doesn't hit +This performs an ``UPDATE`` SQL statement behind the scenes (see the +`How Django knows to UPDATE vs. INSERT`_ section below). Django doesn't hit the database until you explicitly call ``save()``. The ``save()`` method has no return value. +``update(**kwargs)`` +-------------------- + +**New in Django development version** + +A convenience method for updating and saving an object all in one step, where +(``**kwargs``) are the attributes to update. Like ``save()``, the +``update()`` method has no return value. + +Using ``update()``, the above code example could be rewritten as:: + + newblog.update(name="Brave New World") + +Since ``update()`` calls ``save()`` behind the scenes, Django will hit the +database every time ``update()`` is called. + How Django knows to UPDATE vs. INSERT ------------------------------------- @@ -784,6 +802,54 @@ .. _Safe methods: http://www.w3.org/Protocols/rfc2616/rfc2616-sec9.html#sec9.1.1 +``update_or_create(**kwargs)`` +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +**New in Django development version** + +A convenience method for looking up an object with the given kwargs, and then +either updating the values of the object if one is found or creating an +object if one was not found. + +This method calls ``get_or_create()`` behind the scenes, and similarly +returns a tuple of ``(object, created)``, where``object`` is the updated or +created object and ``created`` is a boolean specifying whether a new object +was created. + +This is meant as a shortcut to the following type of code:: + + obj, created = Person.objects.get_or_create(first_name='John', last_name='Lennon', + defaults={'birthday': date(1940, 10, 9)}) + if not created: + obj.update('birthday'=date(1940, 10, 9)) + +This pattern gets quite unwieldy as the number of fields in a model goes up. +The above example can be rewritten using ``update_or_create()`` like so:: + + obj, created = Person.objects.update_or_create(first_name='John', last_name='Lennon', + defaults={'birthday': date(1940, 10, 9)}) + +Any keyword arguments passed to ``update_or_create()`` will be used in a +call to ``get_or_create()``. If ``get_or_create()`` creates an object, then +nothing needs to be done by ``update_or_create()`` and a tuple of the created +object and ``True`` is returned. If, on the other hand, ``get_or_create()`` +does not create a new object, then ``update_or_create()`` will update the +object with the values passed in the ``defaults`` parameter and a tuple of +the updated object and ``True`` is returned. + +The ``defaults`` parameter should be a dict of attribute-value pairs that +you want to update. If ``defaults`` is empty or not specified, then +``update_or_create()`` will act exactly like ``get_or_create()`` since there +would be nothing to update. + +As with ``get_or_create()``, if you need to use ``update_or_create()`` in a +view, please make sure to use it only in ``POST`` requests unless you have a +good reason not to. ``GET`` requests shouldn't have any effect on data; use +``POST`` whenever a request to a page has a side effect on your data. For +more, see `Safe methods`_ in the HTTP spec. + +.. _Safe methods: http://www.w3.org/Protocols/rfc2616/rfc2616-sec9.html#sec9.1.1 + ``count()`` ~~~~~~~~~~~ Modified: django/trunk/docs/settings.txt =================================================================== --- django/trunk/docs/settings.txt 2007-01-03 20:46:26 UTC (rev 4279) +++ django/trunk/docs/settings.txt 2007-01-03 22:37:05 UTC (rev 4280) @@ -157,13 +157,13 @@ Default: ``{}`` (Empty dictionary) -A dictionary mapping ``"app_label.module_name"`` strings to functions that take +A dictionary mapping ``"app_label.model_name"`` strings to functions that take a model object and return its URL. This is a way of overriding ``get_absolute_url()`` methods on a per-installation basis. Example:: ABSOLUTE_URL_OVERRIDES = { - 'blogs.blogs': lambda o: "/blogs/%s/" % o.slug, - 'news.stories': lambda o: "/stories/%s/%s/" % (o.pub_year, o.slug), + 'blogs.Weblog': lambda o: "/blogs/%s/" % o.slug, + 'news.Story': lambda o: "/stories/%s/%s/" % (o.pub_year, o.slug), } ADMIN_FOR --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Django updates" group. To post to this group, send email to django-updates@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/django-updates?hl=en -~----------~----~----~----~------~----~------~--~---
