#10227: OneToOne fields with null=True raise DoesNotExist exception on related
model
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Reporter: rvdrijst | Owner: nobody
Status: new | Milestone:
Component: Database layer (models, ORM) | Version: 1.0
Resolution: | Keywords: onetoone
related expection null
Stage: Design decision needed | Has_patch: 1
Needs_docs: 0 | Needs_tests: 0
Needs_better_patch: 0 |
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Comment (by gsakkis):
I ran into the same problem although in my case a hypothetical
`related_null=True` would not help; a new default object would have be
created. So instead of `related_null` I wrote a OneToOneField that uses
`related_default`, a callable `lambda instance: value`. I posted the
snippet at http://gist.github.com/601977.
To me this seems more elegant, not only because it is a generalization of
the `related_null` (just set `related_default=lambda instance: None`) but
because `null` (and by association `related_null`) is a DB-level
parameter, it determines whether a DB column is created as NULL or NOT
NULL. In the case of a OneToOneField, the related model does not have a
column linking to the model where the OneToOneField was defined (no
`shop_id` column in the place table), so it doesn't make sense to say it's
null.
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Ticket URL: <http://code.djangoproject.com/ticket/10227#comment:10>
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