#20429: Add QuerySet.update_or_create method
-------------------------------------+-------------------------------------
Reporter: tunixman | Owner:
Type: New feature | elektrrrus
Component: Database layer | Status: assigned
(models, ORM) | Version: master
Severity: Normal | Resolution:
Keywords: | Triage Stage: Accepted
Has patch: 1 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
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Comment (by loic84):
As mentioned on IRC, I believe this method suffers from a race-condition
(especially if used in a view) which should be documented.
{{{
Warning:
This method is prone to race-condition and can result in multiple rows
being
inserted simultaneously if uniqueness is not enforced at the database
level
(see either ``unique`` or ``unique_together``).
During a race where uniqueness is inforced, all simultaneous calls to
``create_or_update`` but one will raise an ``IntegrityError``.
Without uniqueness inforcement, any ``create_or_update`` call with the
same set
of parameters that happens after a race will raise
``MultipleObjectsReturned``.
}}}
Like `get_or_create`, it might be good to recommend it as a convenience
for scripts rather than something to use in a view.
Refs #12579
--
Ticket URL: <https://code.djangoproject.com/ticket/20429#comment:22>
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