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Fixed #24881 -- Clarified Meta.order_with_respect_to documentation

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johannes.linke 2015-06-05 22:14:34 +02:00 committed by Tim Graham
parent 0d97e73d95
commit 27c839e0fc
1 changed files with 18 additions and 10 deletions
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docs/ref/models/options.txt
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@ -173,11 +173,11 @@ Django quotes column and table names behind the scenes.
.. attribute:: Options.order_with_respect_to
Marks this object as "orderable" with respect to the given field. This is almost
always used with related objects to allow them to be ordered with respect to a
parent object. For example, if an ``Answer`` relates to a ``Question`` object,
and a question has more than one answer, and the order of answers matters, you'd
do this::
Makes this object orderable with respect to the given field, usually a
``ForeignKey``. This can be used to make related objects orderable with
respect to a parent object. For example, if an ``Answer`` relates to a
``Question`` object, and a question has more than one answer, and the order
of answers matters, you'd do this::
from django.db import models
@ -218,12 +218,20 @@ Django quotes column and table names behind the scenes.
>>> answer.get_previous_in_order()
<Answer: 1>
.. admonition:: Changing order_with_respect_to
.. admonition:: ``order_with_respect_to`` implicitly sets the ``ordering`` option
``order_with_respect_to`` adds an additional field/database column
named ``_order``, so be sure to make and apply the appropriate
migrations if you add or change ``order_with_respect_to``
after your initial :djadmin:`migrate`.
Internally, ``order_with_respect_to`` adds an additional field/database
column named ``_order`` and sets the model's :attr:`~Options.ordering`
option to this field. Consequently, ``order_with_respect_to`` and
``ordering`` cannot be used together, and the ordering added by
``order_with_respect_to`` will apply whenever you obtain a list of objects
of this model.
.. admonition:: Changing ``order_with_respect_to``
Because ``order_with_respect_to`` adds a new database column, be sure to
make and apply the appropriate migrations if you add or change
``order_with_respect_to`` after your initial :djadmin:`migrate`.
``ordering``
------------