The Model.from_db() is intended to be used in cases where customization
of model loading is needed. Reasons can be performance, or adding custom
behavior to the model (for example "dirty field tracking" to issue
automatic update_fields when saving models).
A big thank you to Tim Graham for the review!
Overriding the error messages now works for both unique fields, unique_together
and unique_for_date.
This patch changed the overriding logic to allow customizing NON_FIELD_ERRORS
since previously only fields' errors were customizable.
Refs #20199.
Thanks leahculver for the suggestion.
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.
Although the ModelForm validation code was changed to call
Model.full_clean(), the documentation still said otherwise. The
offending phrase was removed.
Model.save() will use UPDATE - if not updated - INSERT instead of
SELECT - if found UPDATE else INSERT. This should save a query when
updating, but will cost a little when inserting model with PK set.
Also fixed#17341 -- made sure .save() commits transactions only after
the whole model has been saved. This wasn't the case in model
inheritance situations.
The save_base implementation was refactored into multiple methods.
A typical chain for inherited save is:
save_base()
_save_parents(self)
for each parent:
_save_parents(parent)
_save_table(parent)
_save_table(self)
Deferred models now automatically update only the fields which are
loaded from the db (with .only() or .defer()). In addition, any field
set manually after the load is updated on save.
* Renamed smart_unicode to smart_text (but kept the old name under
Python 2 for backwards compatibility).
* Renamed smart_str to smart_bytes.
* Re-introduced smart_str as an alias for smart_text under Python 3
and smart_bytes under Python 2 (which is backwards compatible).
Thus smart_str always returns a str objects.
* Used the new smart_str in a few places where both Python 2 and 3
want a str.
Added the ability to update only part of the model's fields in
model.save() by introducing a new kwarg "update_fields". Thanks
to all the numerous reviewers and commenters in the ticket
Tim Graham
Markus Holtermann
Anssi Kääriäinen
Anubhav Joshi
Ryan Nowakowski
Éric Araujo
chriscauley
Claude Paroz
Alasdair Nicol
Loic Bistuer
evildmp
Eric Boersma
Kevin Christopher Henry
Jimmy Song
Julien Phalip
James Bennett
Marc Egli
Juan Catalano
Jason Yan
Eric Davis
Ramiro Morales
Aymeric Augustin
Alex Gaynor
Andrei Antoukh
Tim Graham
Jacob Kaplan-Moss