mirrors/django
1
0
Fork 0
mirror of https://github.com/django/django.git synced 2025-10-24 14:16:09 +00:00
Code Issues 32 Releases Wiki Activity

Fixed #30446 -- Resolved Value.output_field for stdlib types.

Browse Source 
This required implementing a limited form of dynamic dispatch to combine
expressions with numerical output. Refs #26355 should eventually provide
a better interface for that.
This commit is contained in:
Simon Charette
2019-05-12 17:17:47 -04:00
committed by Mariusz Felisiak
parent d08e6f55e3
commit 1e38f1191d
10 changed files with 122 additions and 39 deletions
Download Patch File Download Diff File Expand all files Collapse all files

10
docs/ref/models/expressions.txt
View File

@@ -484,7 +484,15 @@ The ``output_field`` argument should be a model field instance, like
after it's retrieved from the database. Usually no arguments are needed when
instantiating the model field as any arguments relating to data validation
(``max_length``, ``max_digits``, etc.) will not be enforced on the expression's
output value.
output value. If no ``output_field`` is specified it will be tentatively
inferred from the :py:class:`type` of the provided ``value``, if possible. For
example, passing an instance of :py:class:`datetime.datetime` as ``value``
would default ``output_field`` to :class:`~django.db.models.DateTimeField`.
.. versionchanged:: 3.2
Support for inferring a default ``output_field`` from the type of ``value``
was added.
``ExpressionWrapper()`` expressions
-----------------------------------