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@@ -3,8 +3,8 @@ Model ``Meta`` options
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======================
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This document explains all the possible :ref:`metadata options
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-<meta-options>` that you can give your model in its internal ``class
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-Meta``.
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+<meta-options>` that you can give your model in its internal
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+``class Meta``.
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Available ``Meta`` options
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==========================
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@@ -16,27 +16,28 @@ Available ``Meta`` options
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.. attribute:: Options.abstract
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-If ``True``, this model will be an :ref:`abstract base class <abstract-base-classes>`.
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+ If ``abstract = True``, this model will be an
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+ :ref:`abstract base class <abstract-base-classes>`.
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``app_label``
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-------------
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.. attribute:: Options.app_label
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-If a model exists outside of the standard :file:`models.py` (for instance, if
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-the app's models are in submodules of ``myapp.models``), the model must define
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-which app it is part of::
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+ If a model exists outside of the standard :file:`models.py` (for instance,
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+ if the app's models are in submodules of ``myapp.models``), the model must
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+ define which app it is part of::
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- app_label = 'myapp'
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+ app_label = 'myapp'
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``db_table``
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------------
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.. attribute:: Options.db_table
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-The name of the database table to use for the model::
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+ The name of the database table to use for the model::
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- db_table = 'music_album'
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+ db_table = 'music_album'
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.. _table-names:
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@@ -46,8 +47,8 @@ Table names
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To save you time, Django automatically derives the name of the database table
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from the name of your model class and the app that contains it. A model's
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database table name is constructed by joining the model's "app label" -- the
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-name you used in ``manage.py startapp`` -- to the model's class name, with an
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-underscore between them.
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+name you used in :djadmin:`manage.py startapp <startapp>` -- to the model's
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+class name, with an underscore between them.
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For example, if you have an app ``bookstore`` (as created by
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``manage.py startapp bookstore``), a model defined as ``class Book`` will have
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@@ -65,197 +66,197 @@ Django quotes column and table names behind the scenes.
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.. attribute:: Options.db_tablespace
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-The name of the database tablespace to use for the model. If the backend doesn't
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-support tablespaces, this option is ignored.
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+ The name of the database tablespace to use for the model. If the backend
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+ doesn't support tablespaces, this option is ignored.
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``get_latest_by``
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-----------------
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.. attribute:: Options.get_latest_by
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-The name of a :class:`DateField` or :class:`DateTimeField` in the model. This
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-specifies the default field to use in your model :class:`Manager`'s
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-:class:`~QuerySet.latest` method.
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+ The name of a :class:`DateField` or :class:`DateTimeField` in the model.
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+ This specifies the default field to use in your model :class:`Manager`'s
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+ :class:`~QuerySet.latest` method.
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-Example::
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+ Example::
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- get_latest_by = "order_date"
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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.QuerySet.latest` for more.
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``managed``
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------------------------
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+-----------
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.. attribute:: Options.managed
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-Defaults to ``True``, meaning Django will create the appropriate database
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-tables in :djadmin:`syncdb` and remove them as part of a :djadmin:`reset`
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-management command. That is, Django *manages* the database tables' lifecycles.
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+ Defaults to ``True``, meaning Django will create the appropriate database
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+ tables in :djadmin:`syncdb` and remove them as part of a :djadmin:`reset`
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+ management command. That is, Django *manages* the database tables' lifecycles.
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-If ``False``, no database table creation or deletion operations will be
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-performed for this model. This is useful if the model represents an existing
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-table or a database view that has been created by some other means. This is
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-the *only* difference when ``managed`` is ``False``. All other aspects of
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-model handling are exactly the same as normal. This includes
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+ If ``False``, no database table creation or deletion operations will be
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+ performed for this model. This is useful if the model represents an existing
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+ table or a database view that has been created by some other means. This is
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+ the *only* difference when ``managed=False``. All other aspects of
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+ model handling are exactly the same as normal. This includes
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- 1. Adding an automatic primary key field to the model if you don't declare
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- it. To avoid confusion for later code readers, it's recommended to
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- specify all the columns from the database table you are modeling when
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- using unmanaged models.
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+ 1. Adding an automatic primary key field to the model if you don't declare
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+ it. To avoid confusion for later code readers, it's recommended to
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+ specify all the columns from the database table you are modeling when
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+ using unmanaged models.
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- 2. If a model with ``managed=False`` contains a
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- :class:`~django.db.models.ManyToManyField` that points to another
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- unmanaged model, then the intermediate table for the many-to-many join
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- will also not be created. However, the intermediary table between one
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- managed and one unmanaged model *will* be created.
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+ 2. If a model with ``managed=False`` contains a
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+ :class:`~django.db.models.ManyToManyField` that points to another
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+ unmanaged model, then the intermediate table for the many-to-many join
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+ will also not be created. However, the intermediary table between one
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+ managed and one unmanaged model *will* be created.
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- If you need to change this default behavior, create the intermediary
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- table as an explicit model (with ``managed`` set as needed) and use the
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- :attr:`ManyToManyField.through` attribute to make the relation use your
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- custom model.
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+ If you need to change this default behavior, create the intermediary
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+ table as an explicit model (with ``managed`` set as needed) and use the
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+ :attr:`ManyToManyField.through` attribute to make the relation use your
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+ custom model.
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-For tests involving models with ``managed=False``, it's up to you to ensure
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-the correct tables are created as part of the test setup.
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+ For tests involving models with ``managed=False``, it's up to you to ensure
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+ the correct tables are created as part of the test setup.
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-If you're interested in changing the Python-level behavior of a model class,
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-you *could* use ``managed=False`` and create a copy of an existing model.
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-However, there's a better approach for that situation: :ref:`proxy-models`.
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+ If you're interested in changing the Python-level behavior of a model class,
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+ you *could* use ``managed=False`` and create a copy of an existing model.
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+ However, there's a better approach for that situation: :ref:`proxy-models`.
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``order_with_respect_to``
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-------------------------
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.. attribute:: Options.order_with_respect_to
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-Marks this object as "orderable" with respect to the given field. This is almost
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-always used with related objects to allow them to be ordered with respect to a
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-parent object. For example, if an ``Answer`` relates to a ``Question`` object,
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-and a question has more than one answer, and the order of answers matters, you'd
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-do this::
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+ Marks this object as "orderable" with respect to the given field. This is almost
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+ always used with related objects to allow them to be ordered with respect to a
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+ parent object. For example, if an ``Answer`` relates to a ``Question`` object,
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+ and a question has more than one answer, and the order of answers matters, you'd
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+ do this::
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- class Answer(models.Model):
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- question = models.ForeignKey(Question)
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- # ...
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+ class Answer(models.Model):
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+ question = models.ForeignKey(Question)
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+ # ...
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- class Meta:
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- order_with_respect_to = 'question'
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+ class Meta:
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+ order_with_respect_to = 'question'
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-When ``order_with_respect_to`` is set, two additional methods are provided to
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-retrieve and to set the order of the related objects: ``get_RELATED_order()``
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-and ``set_RELATED_order()``, where ``RELATED`` is the lowercased model name. For
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-example, assuming that a ``Question`` object has multiple related ``Answer``
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-objects, the list returned contains the primary keys of the related ``Answer``
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-objects::
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+ When ``order_with_respect_to`` is set, two additional methods are provided to
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+ retrieve and to set the order of the related objects: ``get_RELATED_order()``
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+ and ``set_RELATED_order()``, where ``RELATED`` is the lowercased model name. For
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+ example, assuming that a ``Question`` object has multiple related ``Answer``
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+ objects, the list returned contains the primary keys of the related ``Answer``
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+ objects::
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- >>> question = Question.objects.get(id=1)
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- >>> question.get_answer_order()
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- [1, 2, 3]
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+ >>> question = Question.objects.get(id=1)
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+ >>> question.get_answer_order()
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+ [1, 2, 3]
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-The order of a ``Question`` object's related ``Answer`` objects can be set by
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-passing in a list of ``Answer`` primary keys::
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+ The order of a ``Question`` object's related ``Answer`` objects can be set by
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+ passing in a list of ``Answer`` primary keys::
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- >>> question.set_answer_order([3, 1, 2])
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+ >>> question.set_answer_order([3, 1, 2])
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-The related objects also get two methods, ``get_next_in_order()`` and
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-``get_previous_in_order()``, which can be used to access those objects in their
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-proper order. Assuming the ``Answer`` objects are ordered by ``id``::
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+ The related objects also get two methods, ``get_next_in_order()`` and
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+ ``get_previous_in_order()``, which can be used to access those objects in their
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+ proper order. Assuming the ``Answer`` objects are ordered by ``id``::
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- >>> answer = Answer.objects.get(id=2)
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- >>> answer.get_next_in_order()
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- <Answer: 3>
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- >>> answer.get_previous_in_order()
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- <Answer: 1>
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+ >>> answer = Answer.objects.get(id=2)
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+ >>> answer.get_next_in_order()
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+ <Answer: 3>
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+ >>> answer.get_previous_in_order()
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+ <Answer: 1>
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``ordering``
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------------
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.. attribute:: Options.ordering
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-The default ordering for the object, for use when obtaining lists of objects::
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+ The default ordering for the object, for use when obtaining lists of objects::
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- ordering = ['-order_date']
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+ ordering = ['-order_date']
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-This is a tuple or list of strings. Each string is a field name with an optional
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-"-" prefix, which indicates descending order. Fields without a leading "-" will
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-be ordered ascending. Use the string "?" to order randomly.
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+ This is a tuple or list of strings. Each string is a field name with an optional
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+ "-" prefix, which indicates descending order. Fields without a leading "-" will
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+ be ordered ascending. Use the string "?" to order randomly.
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-.. note::
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+ .. note::
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- Regardless of how many fields are in :attr:`~Options.ordering`, the admin
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- site uses only the first field.
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+ Regardless of how many fields are in :attr:`~Options.ordering`, the admin
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+ site uses only the first field.
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-For example, to order by a ``pub_date`` field ascending, use this::
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+ For example, to order by a ``pub_date`` field ascending, use this::
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- ordering = ['pub_date']
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+ ordering = ['pub_date']
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-To order by ``pub_date`` descending, use this::
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+ To order by ``pub_date`` descending, use this::
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- ordering = ['-pub_date']
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+ ordering = ['-pub_date']
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-To order by ``pub_date`` descending, then by ``author`` ascending, use this::
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+ To order by ``pub_date`` descending, then by ``author`` ascending, use this::
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- ordering = ['-pub_date', 'author']
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+ ordering = ['-pub_date', 'author']
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``permissions``
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---------------
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.. attribute:: Options.permissions
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-Extra permissions to enter into the permissions table when creating this object.
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-Add, delete and change permissions are automatically created for each object
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-that has ``admin`` set. This example specifies an extra permission,
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-``can_deliver_pizzas``::
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+ Extra permissions to enter into the permissions table when creating this object.
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+ Add, delete and change permissions are automatically created for each object
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+ that has ``admin`` set. This example specifies an extra permission,
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+ ``can_deliver_pizzas``::
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- permissions = (("can_deliver_pizzas", "Can deliver pizzas"),)
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+ permissions = (("can_deliver_pizzas", "Can deliver pizzas"),)
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-This is a list or tuple of 2-tuples in the format ``(permission_code,
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-human_readable_permission_name)``.
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+ This is a list or tuple of 2-tuples in the format ``(permission_code,
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+ human_readable_permission_name)``.
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``proxy``
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---------
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.. attribute:: Options.proxy
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-If set to ``True``, a model which subclasses another model will be treated as
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-a :ref:`proxy model <proxy-models>`.
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+ If ``proxy = True``, a model which subclasses another model will be treated as
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+ a :ref:`proxy model <proxy-models>`.
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``unique_together``
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-------------------
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.. attribute:: Options.unique_together
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-Sets of field names that, taken together, must be unique::
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+ Sets of field names that, taken together, must be unique::
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- unique_together = (("driver", "restaurant"),)
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+ unique_together = (("driver", "restaurant"),)
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-This is a list of lists of fields that must be unique when considered together.
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-It's used in the Django admin and is enforced at the database level (i.e., the
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-appropriate ``UNIQUE`` statements are included in the ``CREATE TABLE``
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-statement).
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+ This is a list of lists of fields that must be unique when considered together.
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+ It's used in the Django admin and is enforced at the database level (i.e., the
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+ appropriate ``UNIQUE`` statements are included in the ``CREATE TABLE``
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+ statement).
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-For convenience, unique_together can be a single list when dealing with a single
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-set of fields::
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+ For convenience, unique_together can be a single list when dealing with a single
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+ set of fields::
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- unique_together = ("driver", "restaurant")
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+ unique_together = ("driver", "restaurant")
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``verbose_name``
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----------------
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.. attribute:: Options.verbose_name
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-A human-readable name for the object, singular::
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+ A human-readable name for the object, singular::
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- verbose_name = "pizza"
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+ verbose_name = "pizza"
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-If this isn't given, Django will use a munged version of the class name:
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-``CamelCase`` becomes ``camel case``.
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+ If this isn't given, Django will use a munged version of the class name:
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+ ``CamelCase`` becomes ``camel case``.
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``verbose_name_plural``
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-----------------------
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.. attribute:: Options.verbose_name_plural
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-The plural name for the object::
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+ The plural name for the object::
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- verbose_name_plural = "stories"
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+ verbose_name_plural = "stories"
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-If this isn't given, Django will use :attr:`~Options.verbose_name` + ``"s"``.
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+ If this isn't given, Django will use :attr:`~Options.verbose_name` + ``"s"``.
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