mirror of https://github.com/django/django.git
Fixed doc references to `django.db.models.query.QuerySet` and converted some tabs that were introduced in r16699 to spaces.
git-svn-id: http://code.djangoproject.com/svn/django/trunk@16915 bcc190cf-cafb-0310-a4f2-bffc1f526a37
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@ -321,9 +321,9 @@ will get you started for now.
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A shortcut: get_object_or_404()
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-------------------------------
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It's a very common idiom to use :meth:`~django.db.models.QuerySet.get` and raise
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:exc:`~django.http.Http404` if the object doesn't exist. Django provides a
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shortcut. Here's the ``detail()`` view, rewritten::
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It's a very common idiom to use :meth:`~django.db.models.query.QuerySet.get`
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and raise :exc:`~django.http.Http404` if the object doesn't exist. Django
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provides a shortcut. Here's the ``detail()`` view, rewritten::
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from django.shortcuts import render_to_response, get_object_or_404
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# ...
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@ -333,8 +333,8 @@ shortcut. Here's the ``detail()`` view, rewritten::
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The :func:`~django.shortcuts.get_object_or_404` function takes a Django model
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as its first argument and an arbitrary number of keyword arguments, which it
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passes to the module's :meth:`~django.db.models.QuerySet.get` function. It
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raises :exc:`~django.http.Http404` if the object doesn't exist.
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passes to the module's :meth:`~django.db.models.query.QuerySet.get` function.
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It raises :exc:`~django.http.Http404` if the object doesn't exist.
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.. admonition:: Philosophy
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@ -349,9 +349,9 @@ raises :exc:`~django.http.Http404` if the object doesn't exist.
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There's also a :func:`~django.shortcuts.get_list_or_404` function, which works
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just as :func:`~django.shortcuts.get_object_or_404` -- except using
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:meth:`~django.db.models.QuerySet.filter` instead of
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:meth:`~django.db.models.QuerySet.get`. It raises :exc:`~django.http.Http404` if
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the list is empty.
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:meth:`~django.db.models.query.QuerySet.filter` instead of
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:meth:`~django.db.models.query.QuerySet.get`. It raises
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:exc:`~django.http.Http404` if the list is empty.
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Write a 404 (page not found) view
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=================================
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@ -388,7 +388,7 @@ MultipleObjectTemplateResponseMixin
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that operate upon a list of object instances. Requires that the view it is
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mixed with provides ``self.object_list``, the list of object instances that
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the view is operating on. ``self.object_list`` may be, but is not required
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to be, a :class:`~django.db.models.Queryset`.
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to be, a :class:`~django.db.models.query.QuerySet`.
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**Extends**
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@ -814,7 +814,7 @@ BaseDateListView
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Returns the list of dates of type ``date_type`` for which
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``queryset`` contains entries. For example, ``get_date_list(qs,
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'year')`` will return the list of years for which ``qs`` has entries.
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See :meth:`~django.db.models.QuerySet.dates()` for the
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See :meth:`~django.db.models.query.QuerySet.dates()` for the
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ways that the ``date_type`` argument can be used.
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@ -23,8 +23,9 @@ models. For example, here's the user module from Django's built-in
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.. warning::
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The "delete selected objects" action uses :meth:`QuerySet.delete()
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<django.db.models.QuerySet.delete>` for efficiency reasons, which has an
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important caveat: your model's ``delete()`` method will not be called.
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<django.db.models.query.QuerySet.delete>` for efficiency reasons, which
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has an important caveat: your model's ``delete()`` method will not be
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called.
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If you wish to override this behavior, simply write a custom action which
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accomplishes deletion in your preferred manner -- for example, by calling
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@ -74,8 +75,8 @@ three arguments:
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* The current :class:`ModelAdmin`
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* An :class:`~django.http.HttpRequest` representing the current request,
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* A :class:`~django.db.models.QuerySet` containing the set of objects
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selected by the user.
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* A :class:`~django.db.models.query.QuerySet` containing the set of
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objects selected by the user.
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Our publish-these-articles function won't need the :class:`ModelAdmin` or the
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request object, but we will use the queryset::
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@ -713,13 +713,14 @@ subclass::
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.. attribute:: ModelAdmin.list_select_related
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Set ``list_select_related`` to tell Django to use
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:meth:`~django.db.models.QuerySet.select_related` in retrieving the list of
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objects on the admin change list page. This can save you a bunch of
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database queries.
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:meth:`~django.db.models.query.QuerySet.select_related` in retrieving
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the list of objects on the admin change list page. This can save you a
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bunch of database queries.
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The value should be either ``True`` or ``False``. Default is ``False``.
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Note that Django will use :meth:`~django.db.models.QuerySet.select_related`,
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Note that Django will use
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:meth:`~django.db.models.query.QuerySet.select_related`,
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regardless of this setting if one of the ``list_display`` fields is a
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``ForeignKey``.
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@ -1182,9 +1183,9 @@ templates used by the :class:`ModelAdmin` views:
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.. method:: ModelAdmin.queryset(self, request)
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The ``queryset`` method on a ``ModelAdmin`` returns a
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:class:`~django.db.models.QuerySet` of all model instances that can be
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edited by the admin site. One use case for overriding this method is
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to show objects owned by the logged-in user::
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:class:`~django.db.models.query.QuerySet` of all model instances that
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can be edited by the admin site. One use case for overriding this method
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is to show objects owned by the logged-in user::
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class MyModelAdmin(admin.ModelAdmin):
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def queryset(self, request):
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@ -116,7 +116,8 @@ model it represents, or to retrieve objects from that model:
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Takes a set of valid :ref:`lookup arguments <field-lookups-intro>` for the
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model the :class:`~django.contrib.contenttypes.models.ContentType`
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represents, and does :meth:`a get() lookup <django.db.models.QuerySet.get>`
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represents, and does
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:meth:`a get() lookup <django.db.models.query.QuerySet.get>`
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on that model, returning the corresponding object.
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.. method:: ContentType.model_class()
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@ -416,9 +417,9 @@ might be tempted to try something like::
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This will not work correctly, however. The generic relation adds extra filters
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to the queryset to ensure the correct content type, but the
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:meth:`~django.db.models.QuerySet.aggregate` method doesn't take them into
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account. For now, if you need aggregates on generic relations, you'll need
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to calculate them without using the aggregation API.
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:meth:`~django.db.models.query.QuerySet.aggregate` method doesn't take them
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into account. For now, if you need aggregates on generic relations, you'll
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need to calculate them without using the aggregation API.
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Generic relations in forms and admin
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------------------------------------
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@ -119,7 +119,7 @@ A complete reference can be found in the :ref:`spatial lookup reference
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.. note::
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GeoDjango constructs spatial SQL with the :class:`GeoQuerySet`, a
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subclass of :class:`~django.db.models.QuerySet`. The
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subclass of :class:`~django.db.models.query.QuerySet`. The
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:class:`GeoManager` instance attached to your model is what
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enables use of :class:`GeoQuerySet`.
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@ -89,7 +89,7 @@ Django quotes column and table names behind the scenes.
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get_latest_by = "order_date"
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See the docs for :meth:`~django.db.models.QuerySet.latest` for more.
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See the docs for :meth:`~django.db.models.query.QuerySet.latest` for more.
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``managed``
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-----------
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@ -106,11 +106,11 @@ described here.
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.. admonition:: You can't share pickles between versions
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Pickles of QuerySets are only valid for the version of Django that
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was used to generate them. If you generate a pickle using Django
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version N, there is no guarantee that pickle will be readable with
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Django version N+1. Pickles should not be used as part of a long-term
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archival strategy.
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Pickles of QuerySets are only valid for the version of Django that
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was used to generate them. If you generate a pickle using Django
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version N, there is no guarantee that pickle will be readable with
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Django version N+1. Pickles should not be used as part of a long-term
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archival strategy.
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.. _queryset-api:
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@ -133,9 +133,9 @@ Though you usually won't create one manually — you'll go through a
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.. attribute:: ordered
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``True`` if the ``QuerySet`` is ordered — i.e. has an
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:meth:`order_by()` clause or a default ordering on the model.
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``False`` otherwise.
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``True`` if the ``QuerySet`` is ordered — i.e. has an
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:meth:`order_by()` clause or a default ordering on the model.
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``False`` otherwise.
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.. attribute:: db
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@ -468,8 +468,8 @@ This restriction has been lifted, and you can now also refer to fields on
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related models with reverse relations through ``OneToOneField``, ``ForeignKey``
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and ``ManyToManyField`` attributes::
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Blog.objects.values('name', 'entry__headline')
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[{'name': 'My blog', 'entry__headline': 'An entry'},
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Blog.objects.values('name', 'entry__headline')
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[{'name': 'My blog', 'entry__headline': 'An entry'},
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{'name': 'My blog', 'entry__headline': 'Another entry'}, ...]
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.. warning::
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@ -788,62 +788,64 @@ of the arguments is required, but you should use at least one of them.
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SELECT * FROM blog_entry WHERE id IN (3, 4, 5, 20);
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Be careful when using the ``tables`` parameter if you're specifying
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tables that are already used in the query. When you add extra tables
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via the ``tables`` parameter, Django assumes you want that table
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included an extra time, if it is already included. That creates a
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problem, since the table name will then be given an alias. If a table
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appears multiple times in an SQL statement, the second and subsequent
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occurrences must use aliases so the database can tell them apart. If
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you're referring to the extra table you added in the extra ``where``
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parameter this is going to cause errors.
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Be careful when using the ``tables`` parameter if you're specifying
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tables that are already used in the query. When you add extra tables
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via the ``tables`` parameter, Django assumes you want that table
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included an extra time, if it is already included. That creates a
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problem, since the table name will then be given an alias. If a table
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appears multiple times in an SQL statement, the second and subsequent
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occurrences must use aliases so the database can tell them apart. If
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you're referring to the extra table you added in the extra ``where``
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parameter this is going to cause errors.
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Normally you'll only be adding extra tables that don't already appear
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in the query. However, if the case outlined above does occur, there are
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a few solutions. First, see if you can get by without including the
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extra table and use the one already in the query. If that isn't
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possible, put your ``extra()`` call at the front of the queryset
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construction so that your table is the first use of that table.
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Finally, if all else fails, look at the query produced and rewrite your
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``where`` addition to use the alias given to your extra table. The
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alias will be the same each time you construct the queryset in the same
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way, so you can rely upon the alias name to not change.
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Normally you'll only be adding extra tables that don't already appear
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in the query. However, if the case outlined above does occur, there are
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a few solutions. First, see if you can get by without including the
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extra table and use the one already in the query. If that isn't
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possible, put your ``extra()`` call at the front of the queryset
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construction so that your table is the first use of that table.
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Finally, if all else fails, look at the query produced and rewrite your
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``where`` addition to use the alias given to your extra table. The
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alias will be the same each time you construct the queryset in the same
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way, so you can rely upon the alias name to not change.
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* ``order_by``
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If you need to order the resulting queryset using some of the new
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fields or tables you have included via ``extra()`` use the ``order_by``
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parameter to ``extra()`` and pass in a sequence of strings. These
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strings should either be model fields (as in the normal
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:meth:`order_by()` method on querysets), of the form
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``table_name.column_name`` or an alias for a column that you specified
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in the ``select`` parameter to ``extra()``.
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If you need to order the resulting queryset using some of the new
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fields or tables you have included via ``extra()`` use the ``order_by``
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parameter to ``extra()`` and pass in a sequence of strings. These
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strings should either be model fields (as in the normal
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:meth:`order_by()` method on querysets), of the form
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``table_name.column_name`` or an alias for a column that you specified
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in the ``select`` parameter to ``extra()``.
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For example::
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q = Entry.objects.extra(select={'is_recent': "pub_date > '2006-01-01'"})
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q = q.extra(order_by = ['-is_recent'])
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This would sort all the items for which ``is_recent`` is true to the
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front of the result set (``True`` sorts before ``False`` in a
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descending ordering).
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This would sort all the items for which ``is_recent`` is true to the
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front of the result set (``True`` sorts before ``False`` in a
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descending ordering).
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This shows, by the way, that you can make multiple calls to ``extra()``
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and it will behave as you expect (adding new constraints each time).
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This shows, by the way, that you can make multiple calls to ``extra()``
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and it will behave as you expect (adding new constraints each time).
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* ``params``
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The ``where`` parameter described above may use standard Python
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database string placeholders — ``'%s'`` to indicate parameters the
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database engine should automatically quote. The ``params`` argument is
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a list of any extra parameters to be substituted.
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The ``where`` parameter described above may use standard Python
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database string placeholders — ``'%s'`` to indicate parameters the
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database engine should automatically quote. The ``params`` argument is
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a list of any extra parameters to be substituted.
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Example::
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Entry.objects.extra(where=['headline=%s'], params=['Lennon'])
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Always use ``params`` instead of embedding values directly into
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``where`` because ``params`` will ensure values are quoted correctly
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according to your particular backend. For example, quotes will be
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escaped correctly.
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Always use ``params`` instead of embedding values directly into
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``where`` because ``params`` will ensure values are quoted correctly
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according to your particular backend. For example, quotes will be
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escaped correctly.
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Bad::
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@ -70,8 +70,8 @@ particular fields, you can now tell Django not to retrieve them from the
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database.
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You'll do this with the new queryset methods
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:meth:`~django.db.models.QuerySet.defer` and
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:meth:`~django.db.models.QuerySet.only`.
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:meth:`~django.db.models.query.QuerySet.defer` and
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:meth:`~django.db.models.query.QuerySet.only`.
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New admin features
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------------------
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|
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@ -257,8 +257,8 @@ particular fields, you can now tell Django not to retrieve them from the
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database.
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You'll do this with the new queryset methods
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:meth:`~django.db.models.QuerySet.defer` and
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:meth:`~django.db.models.QuerySet.only`.
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:meth:`~django.db.models.query.QuerySet.defer` and
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:meth:`~django.db.models.query.QuerySet.only`.
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Testing improvements
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--------------------
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|
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@ -349,10 +349,10 @@ without any harmful effects, since that is already playing a role in the
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query.
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This behavior is the same as that noted in the queryset documentation for
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:meth:`~django.db.models.QuerySet.distinct` and the general rule is the same:
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normally you won't want extra columns playing a part in the result, so clear
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out the ordering, or at least make sure it's restricted only to those fields
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you also select in a ``values()`` call.
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:meth:`~django.db.models.query.QuerySet.distinct` and the general rule is the
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same: normally you won't want extra columns playing a part in the result, so
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clear out the ordering, or at least make sure it's restricted only to those
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fields you also select in a ``values()`` call.
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.. note::
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You might reasonably ask why Django doesn't remove the extraneous columns
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|
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@ -101,7 +101,7 @@ Use ``iterator()``
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When you have a lot of objects, the caching behavior of the ``QuerySet`` can
|
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cause a large amount of memory to be used. In this case,
|
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:meth:`~django.db.models.QuerySet.iterator()` may help.
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:meth:`~django.db.models.query.QuerySet.iterator()` may help.
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Do database work in the database rather than in Python
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======================================================
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@ -122,7 +122,7 @@ Use ``QuerySet.extra()``
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------------------------
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A less portable but more powerful method is
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:meth:`~django.db.models.QuerySet.extra()`, which allows some SQL to be
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:meth:`~django.db.models.query.QuerySet.extra()`, which allows some SQL to be
|
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explicitly added to the query. If that still isn't powerful enough:
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Use raw SQL
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|
@ -159,7 +159,8 @@ Use ``QuerySet.values()`` and ``values_list()``
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-----------------------------------------------
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When you just want a ``dict`` or ``list`` of values, and don't need ORM model
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objects, make appropriate usage of :meth:`~django.db.models.QuerySet.values()`.
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objects, make appropriate usage of
|
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:meth:`~django.db.models.query.QuerySet.values()`.
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These can be useful for replacing model objects in template code - as long as
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the dicts you supply have the same attributes as those used in the template,
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you are fine.
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|
@ -167,9 +168,9 @@ you are fine.
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Use ``QuerySet.defer()`` and ``only()``
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---------------------------------------
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Use :meth:`~django.db.models.QuerySet.defer()` and
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:meth:`~django.db.models.QuerySet.only()` if there are database columns you
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know that you won't need (or won't need in most cases) to avoid loading
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Use :meth:`~django.db.models.query.QuerySet.defer()` and
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:meth:`~django.db.models.query.QuerySet.only()` if there are database columns
|
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you know that you won't need (or won't need in most cases) to avoid loading
|
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them. Note that if you *do* use them, the ORM will have to go and get them in
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a separate query, making this a pessimization if you use it inappropriately.
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|
|
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@ -346,7 +346,7 @@ This is roughly equivalent to::
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|
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Note, however, that the first of these will raise ``IndexError`` while the
|
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second will raise ``DoesNotExist`` if no objects match the given criteria. See
|
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:meth:`~django.db.models.QuerySet.get` for more details.
|
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:meth:`~django.db.models.query.QuerySet.get` for more details.
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.. _field-lookups-intro:
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|
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|
|
|
@ -124,8 +124,8 @@ Fields may also be left out::
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>>> people = Person.objects.raw('SELECT id, first_name FROM myapp_person')
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|
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The ``Person`` objects returned by this query will be deferred model instances
|
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(see :meth:`~django.db.models.QuerySet.defer()`). This means that the fields
|
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that are omitted from the query will be loaded on demand. For example::
|
||||
(see :meth:`~django.db.models.query.QuerySet.defer()`). This means that the
|
||||
fields that are omitted from the query will be loaded on demand. For example::
|
||||
|
||||
>>> for p in Person.objects.raw('SELECT id, first_name FROM myapp_person'):
|
||||
... print p.first_name, # This will be retrieved by the original query
|
||||
|
|
|
@ -21,9 +21,10 @@ At the highest level, serializing data is a very simple operation::
|
|||
data = serializers.serialize("xml", SomeModel.objects.all())
|
||||
|
||||
The arguments to the ``serialize`` function are the format to serialize the data
|
||||
to (see `Serialization formats`_) and a :class:`~django.db.models.QuerySet` to
|
||||
serialize. (Actually, the second argument can be any iterator that yields Django
|
||||
objects, but it'll almost always be a QuerySet).
|
||||
to (see `Serialization formats`_) and a
|
||||
:class:`~django.db.models.query.QuerySet` to serialize. (Actually, the second
|
||||
argument can be any iterator that yields Django objects, but it'll almost
|
||||
always be a QuerySet).
|
||||
|
||||
You can also use a serializer object directly::
|
||||
|
||||
|
|
|
@ -334,7 +334,7 @@ class CategoryItem(models.Model):
|
|||
category = models.ForeignKey(SimpleCategory)
|
||||
|
||||
def __unicode__(self):
|
||||
return "category item: " + str(self.category)
|
||||
return "category item: " + str(self.category)
|
||||
|
||||
class OneToOneCategory(models.Model):
|
||||
new_name = models.CharField(max_length=15)
|
||||
|
|
Loading…
Reference in New Issue