This deprecates use_for_related_fields.
Old API:
class CustomManager(models.Model):
use_for_related_fields = True
class Model(models.Model):
custom_manager = CustomManager()
New API:
class Model(models.Model):
custom_manager = CustomManager()
class Meta:
base_manager_name = 'custom_manager'
Refs #20932, #25897.
Thanks Carl Meyer for the guidance throughout this work.
Thanks Tim Graham for writing the docs.
The `remove()` and `clear()` methods of the related managers created by
`ForeignKey`, `GenericForeignKey`, and `ManyToManyField` suffered from a
number of issues. Some operations ran multiple data modifying queries without
wrapping them in a transaction, and some operations didn't respect default
filtering when it was present (i.e. when the default manager on the related
model implemented a custom `get_queryset()`).
Fixing the issues introduced some backward incompatible changes:
- The implementation of `remove()` for `ForeignKey` related managers changed
from a series of `Model.save()` calls to a single `QuerySet.update()` call.
The change means that `pre_save` and `post_save` signals aren't called anymore.
- The `remove()` and `clear()` methods for `GenericForeignKey` related
managers now perform bulk delete so `Model.delete()` isn't called anymore.
- The `remove()` and `clear()` methods for `ManyToManyField` related
managers perform nested queries when filtering is involved, which may
or may not be an issue depending on the database and the data itself.
Refs. #3871, #21174.
Thanks Anssi Kääriäinen and Tim Graham for the reviews.
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.
shanghui
Tim Graham
Mads Jensen
Bruno Alla
Claude Paroz
za
Jon Dufresne
Loïc Bistuer
Hasan
Aric Coady
Jonas Degrave
Andriy Sokolovskiy
Markus Holtermann
Shabda Raaj
Anssi Kääriäinen
Loic Bistuer
Alasdair Nicol
Alex Gaynor
Julien Phalip
Marc Tamlyn
Florian Apolloner