diff options
Diffstat (limited to 'docs/ref')
| -rw-r--r-- | docs/ref/models/expressions.txt | 32 | ||||
| -rw-r--r-- | docs/ref/models/querysets.txt | 8 |
2 files changed, 28 insertions, 12 deletions
diff --git a/docs/ref/models/expressions.txt b/docs/ref/models/expressions.txt index 31d2572288..0c6ff1e79e 100644 --- a/docs/ref/models/expressions.txt +++ b/docs/ref/models/expressions.txt @@ -90,10 +90,10 @@ Built-in Expressions .. class:: F -An ``F()`` object represents the value of a model field or annotated column. It -makes it possible to refer to model field values and perform database -operations using them without actually having to pull them out of the database -into Python memory. +An ``F()`` object represents the value of a model field, transformed value of a +model field, or annotated column. It makes it possible to refer to model field +values and perform database operations using them without actually having to +pull them out of the database into Python memory. Instead, Django uses the ``F()`` object to generate an SQL expression that describes the required operation at the database level. @@ -155,6 +155,10 @@ the field value of each one, and saving each one back to the database:: * getting the database, rather than Python, to do work * reducing the number of queries some operations require +.. versionchanged:: 3.2 + + Support for transforms of the field was added. + .. _avoiding-race-conditions-using-f: Avoiding race conditions using ``F()`` @@ -406,9 +410,9 @@ The ``Aggregate`` API is as follows: allows passing a ``distinct`` keyword argument. If set to ``False`` (default), ``TypeError`` is raised if ``distinct=True`` is passed. -The ``expressions`` positional arguments can include expressions or the names -of model fields. They will be converted to a string and used as the -``expressions`` placeholder within the ``template``. +The ``expressions`` positional arguments can include expressions, transforms of +the model field, or the names of model fields. They will be converted to a +string and used as the ``expressions`` placeholder within the ``template``. The ``output_field`` argument requires a model field instance, like ``IntegerField()`` or ``BooleanField()``, into which Django will load the value @@ -435,6 +439,10 @@ and :ref:`filtering-on-annotations` for example usage. The ``**extra`` kwargs are ``key=value`` pairs that can be interpolated into the ``template`` attribute. +.. versionchanged:: 3.2 + + Support for transforms of the field was added. + Creating your own Aggregate Functions ------------------------------------- @@ -551,9 +559,9 @@ Referencing columns from the outer queryset .. class:: OuterRef(field) Use ``OuterRef`` when a queryset in a ``Subquery`` needs to refer to a field -from the outer query. It acts like an :class:`F` expression except that the -check to see if it refers to a valid field isn't made until the outer queryset -is resolved. +from the outer query or its transform. It acts like an :class:`F` expression +except that the check to see if it refers to a valid field isn't made until the +outer queryset is resolved. Instances of ``OuterRef`` may be used in conjunction with nested instances of ``Subquery`` to refer to a containing queryset that isn't the immediate @@ -562,6 +570,10 @@ parent. For example, this queryset would need to be within a nested pair of >>> Book.objects.filter(author=OuterRef(OuterRef('pk'))) +.. versionchanged:: 3.2 + + Support for transforms of the field was added. + Limiting a subquery to a single column ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ diff --git a/docs/ref/models/querysets.txt b/docs/ref/models/querysets.txt index c1a8fd1f3d..85c6bf6b17 100644 --- a/docs/ref/models/querysets.txt +++ b/docs/ref/models/querysets.txt @@ -3525,8 +3525,12 @@ All aggregates have the following parameters in common: ``expressions`` ~~~~~~~~~~~~~~~ -Strings that reference fields on the model, or :doc:`query expressions -</ref/models/expressions>`. +Strings that reference fields on the model, transforms of the field, or +:doc:`query expressions </ref/models/expressions>`. + +.. versionchanged:: 3.2 + + Support for transforms of the field was added. ``output_field`` ~~~~~~~~~~~~~~~~ |