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Simplified Model.save() a bit.

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葛汉斌 2019-05-28 21:40:31 +08:00 committed by Mariusz Felisiak
parent 67b6cb7723
commit fcbc502af9
2 changed files with 16 additions and 14 deletions
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1
AUTHORS
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@ -305,6 +305,7 @@ answer newbie questions, and generally made Django that much better:
Gasper Koren
Gasper Zejn <zejn@kiberpipa.org>
Gavin Wahl <gavinwahl@gmail.com>
Ge Hanbin <xiaomiba0904@gmail.com>
geber@datacollect.com
Geert Vanderkelen
George Karpenkov <george@metaworld.ru>

29
django/db/models/base.py
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@ -678,28 +678,29 @@ class Model(metaclass=ModelBase):
# been assigned and there's no need to worry about this check.
if field.is_relation and field.is_cached(self):
obj = getattr(self, field.name, None)
if not obj:
continue
# A pk may have been assigned manually to a model instance not
# saved to the database (or auto-generated in a case like
# UUIDField), but we allow the save to proceed and rely on the
# database to raise an IntegrityError if applicable. If
# constraints aren't supported by the database, there's the
# unavoidable risk of data corruption.
if obj:
if obj.pk is None:
# Remove the object from a related instance cache.
if not field.remote_field.multiple:
field.remote_field.delete_cached_value(obj)
raise ValueError(
"save() prohibited to prevent data loss due to "
"unsaved related object '%s'." % field.name
)
elif getattr(self, field.attname) is None:
# Use pk from related object if it has been saved after
# an assignment.
setattr(self, field.attname, obj.pk)
if obj.pk is None:
# Remove the object from a related instance cache.
if not field.remote_field.multiple:
field.remote_field.delete_cached_value(obj)
raise ValueError(
"save() prohibited to prevent data loss due to "
"unsaved related object '%s'." % field.name
)
elif getattr(self, field.attname) is None:
# Use pk from related object if it has been saved after
# an assignment.
setattr(self, field.attname, obj.pk)
# If the relationship's pk/to_field was changed, clear the
# cached relationship.
if obj and getattr(obj, field.target_field.attname) != getattr(self, field.attname):
if getattr(obj, field.target_field.attname) != getattr(self, field.attname):
field.delete_cached_value(self)
using = using or router.db_for_write(self.__class__, instance=self)