#17332: Doing a save after primary key has changed should raise an error
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Reporter: akaariai | Owner: nobody
Type: Uncategorized | Status: new
Component: Database layer (models, ORM) | Version: 1.3
Severity: Normal | Keywords:
Triage Stage: Unreviewed | Has patch: 0
Easy pickings: 0 | UI/UX: 0
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Currently, if you change primary key and do a save(), you will get a
duplicate in the database. In effect, the current behavior of save is:
"save the object to DB, except when PK has changed, then do a clone". This
API is not good for natural primary keys. Natural primary keys aren't that
common currently, but if multicolumn primary keys are introduced into
Django, they will be more common.
The idea is to deprecate the current clone behavior of save raise an error
instead. This would need to go through the normal deprecation cycle. You
can get the current behavior back by using .save(clone=True). For
`AutoFields`, setting the pk to None will work.
For implementation the problems are: How to trac primary key changes? Some
fields are mutable inplace, which makes the problem harder. Model
`__init__` should not be made much slower by this.
Some related tickets: #2259, #4102. There is also a
[https://groups.google.com/group/django-
developers/browse_thread/thread/b028e3c7a366330e/58c37e1988d5d8ef#58c37e1988d5d8ef
Django-developers thread] about this.
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Ticket URL: <https://code.djangoproject.com/ticket/17332>
Django <https://code.djangoproject.com/>
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