#9519: Add QuerySet.bulk_delete() that issues only a single SQL query
-------------------------------------+-------------------------------------
Reporter: Tarken | Owner: tobias
Type: New | Status: assigned
feature | Component: Database layer
Milestone: | (models, ORM)
Version: SVN | Severity: Normal
Resolution: | Keywords: database, queryset,
Triage Stage: Accepted | delete
Needs documentation: 0 | Has patch: 0
Patch needs improvement: 0 | Needs tests: 0
UI/UX: 0 | Easy pickings: 0
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Changes (by carljm):
* version: 1.0 => SVN
* stage: Design decision needed => Accepted
Comment:
.delete() has to be implemented the way it is in order to support cascade-
deletion. If Django didn't do cascade-deletion in the ORM it would be much
more difficult to write cross-database-compatible ORM code. So the
implementation of .delete() is not going to change (it does do the cascade
more efficiently now, since #7539 was fixed, than it did when this ticket
was filed).
The issue reported originally here (that deletion doesn't work with
duplicate PKs) is a non-issue. Django's ORM assumes PKs are unique, and
the database will enforce that unless your database is broken or you've
manually modified the tables. That's not going to change, regardless of
what hacky workarounds were suggested on #373.
All that said, I'd be open to a new .bulk_delete() method (parallel to the
.bulk_create() method that was recently added) that would do deletion as
requested here. It would have a number of caveats, primarily that it
wouldn't do FK cascades, so you'd have to have your database set up
correctly to handle that natively (ON DELETE CASCADE or whatnot) or you
might get integrity errors.
natevw, if you think the documentation for the current .delete() method
could better explain its limitations, that's a separate issue - please
file a new ticket for it, ideally with a patch to the docs.
--
Ticket URL: <https://code.djangoproject.com/ticket/9519#comment:9>
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