This patch introduces the Prefetch object which allows customizing prefetch
operations.
This enables things like filtering prefetched relations, calling select_related
from a prefetched relation, or prefetching the same relation multiple times
with different querysets.
When a Prefetch instance specifies a to_attr argument, the result is stored
in a list rather than a QuerySet. This has the fortunate consequence of being
significantly faster. The preformance improvement is due to the fact that we
save the costly creation of a QuerySet instance.
Thanks @akaariai for the original patch and @bmispelon and @timgraham
for the reviews.
Thanks dan at dlo.me for the initial patch.
- Added __pow__ and __rpow__ to ExpressionNode
- Added oracle and mysql specific power expressions
- Added used-defined power function for sqlite
select_related('foo').select_related('bar') is now equivalent to
select_related('foo', 'bar').
Also reworded docs to recommend select_related(*fields) over select_related()
The option can be used to force pre 1.6 style SELECT on save behaviour.
This is needed in case the database returns zero updated rows even if
there is a matching row in the DB. One such case is PostgreSQL update
trigger that returns NULL.
Reviewed by Tim Graham.
Refs #16649
The __eq__ method now considers two instances without primary key value
equal only when they have same id(). The __hash__ method raises
TypeError for no primary key case.
Fixed#18864, fixed#18250
Thanks to Tim Graham for docs review.
Added OneToOneField to the list of model fields for which the unique
argument isn't valid. (OneToOneFields are inherently unique, and if
the user supplies a value for unique it is ignored / overwritten.)
Although the ModelForm validation code was changed to call
Model.full_clean(), the documentation still said otherwise. The
offending phrase was removed.
Added OneToOneField to the list of model fields for which the unique
argument isn't valid. (OneToOneFields are inherently unique, and if
the user supplies a value for unique it is ignored / overwritten.)
Sphinx generates left single quotes for apostrophes after
code markup, when right single quotes are required. The
easiest way to fix this is just by inserting the unicode
character for a right single quote.
Instances of the problem were found by looking for
">‘" in the generated HTML.
Additionally this patch solves the orthogonal problem that specialized
`QuerySet` like `ValuesQuerySet` didn't inherit from the current `QuerySet`
type. This wasn't an issue until now because we didn't officially support
custom `QuerySet` but it became necessary with the introduction of this new
feature.
Thanks aaugustin, akaariai, carljm, charettes, mjtamlyn, shaib and timgraham
for the reviews.
Loic Bistuer
Baptiste Mispelon
Tim Graham
Shai Berger
Florian Hahn
Juergen Schackmann
Marc Tamlyn
Erik Romijn
mlissner
Matt Austin
e0ne
Aymeric Augustin
Matthew Rich
Daniele Procida
Eric Boersma
Anssi Kääriäinen
Andrew Godwin
Kevin Christopher Henry
Preston Holmes
Christopher Medrela
Dominic Rodger
Jimmy Song
Curtis Maloney
Alex Couper
Julien Phalip