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Fixed #11557 -- Added support for a list of fields in Meta.get_latest_by and QuerySet.earliest()/latest().

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François Freitag
2017-06-21 13:28:16 -07:00
committed by Tim Graham
parent 093fd479d6
commit ad4a8acdb5
7 changed files with 137 additions and 32 deletions
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14
docs/ref/models/options.txt
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@@ -131,18 +131,26 @@ Django quotes column and table names behind the scenes.
.. attribute:: Options.get_latest_by
The name of an orderable field in the model, typically a :class:`DateField`,
:class:`DateTimeField`, or :class:`IntegerField`. This specifies the default
field to use in your model :class:`Manager`’s
The name of a field or a list of field names in the model, typically
:class:`DateField`, :class:`DateTimeField`, or :class:`IntegerField`. This
specifies the default field(s) to use in your model :class:`Manager`’s
:meth:`~django.db.models.query.QuerySet.latest` and
:meth:`~django.db.models.query.QuerySet.earliest` methods.
Example::
# Latest by ascending order_date.
get_latest_by = "order_date"
# Latest by priority descending, order_date ascending.
get_latest_by = ['-priority', 'order_date']
See the :meth:`~django.db.models.query.QuerySet.latest` docs for more.
.. versionchanged:: 2.0
Support for a list of fields was added.
``managed``
-----------

27
docs/ref/models/querysets.txt
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@@ -2099,20 +2099,29 @@ psycopg mailing list <https://www.postgresql.org/message-id/4D2F2C71.8080805%40d
``latest()``
~~~~~~~~~~~~
.. method:: latest(field_name=None)
.. method:: latest(*fields)
Returns the latest object in the table, by date, using the ``field_name``
provided as the date field.
Returns the latest object in the table based on the given field(s).
This example returns the latest ``Entry`` in the table, according to the
``pub_date`` field::
Entry.objects.latest('pub_date')
You can also choose the latest based on several fields. For example, to select
the ``Entry`` with the earliest ``expire_date`` when two entries have the same
``pub_date``::
Entry.objects.latest('pub_date', '-expire_date')
The negative sign in ``'-expire_date'`` means to sort ``expire_date`` in
*descending* order. Since ``latest()`` gets the last result, the ``Entry`` with
the earliest ``expire_date`` is selected.
If your model's :ref:`Meta <meta-options>` specifies
:attr:`~django.db.models.Options.get_latest_by`, you can leave off the
``field_name`` argument to ``earliest()`` or ``latest()``. Django will use the
field specified in :attr:`~django.db.models.Options.get_latest_by` by default.
:attr:`~django.db.models.Options.get_latest_by`, you can omit any arguments to
``earliest()`` or ``latest()``. The fields specified in
:attr:`~django.db.models.Options.get_latest_by` will be used by default.
Like :meth:`get()`, ``earliest()`` and ``latest()`` raise
:exc:`~django.db.models.Model.DoesNotExist` if there is no object with the
@@ -2121,6 +2130,10 @@ given parameters.
Note that ``earliest()`` and ``latest()`` exist purely for convenience and
readability.
.. versionchanged:: 2.0
Support for several arguments was added.
.. admonition:: ``earliest()`` and ``latest()`` may return instances with null dates.
Since ordering is delegated to the database, results on fields that allow
@@ -2135,7 +2148,7 @@ readability.
``earliest()``
~~~~~~~~~~~~~~
.. method:: earliest(field_name=None)
.. method:: earliest(*fields)
Works otherwise like :meth:`~django.db.models.query.QuerySet.latest` except
the direction is changed.