#30894: Reverse OneToOneField relation: `prefetch_related` uses `related_name`
while `select_related` uses `related_query_name`
-------------------------------------+-------------------------------------
Reporter: Adam Sołtysik | Owner: nobody
Type: | Status: closed
Cleanup/optimization |
Component: Database layer | Version: 2.2
(models, ORM) |
Severity: Normal | Resolution: wontfix
Keywords: | Triage Stage:
| Unreviewed
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
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Changes (by Carlton Gibson):
* component: Documentation => Database layer (models, ORM)
Comment:
Hey Simon. I'm happy if you want to reopen and Accept, but I'm not
entirely sure it's the best change...
`related_query_name` serves when to make filtering a little prettier where
the `related_name` doesn't read right, i.e. you might want to write
`...filter(tag__name='...')` rather that `...filter(tag_set__name='...')`
(or `tags` being the example from the docs). That reads better because
you're saying ''where the tag name is ...'', i.e. checking the property on
the individual, rather than the set.
But with `prefetch_related()`, you want to prefetch the set, so you want
`prefetch_related('tag_set')` (or `tags`) — you **want** the
`related_name`.
(So if the issue is inconsistency, maybe it's `select_related` that has it
backwards — via `get_related_name()`, but we can't change that now I'd
guess...)
Q: how does `get_prefetcher()` look if we're **not** retrieving the actual
descriptor off of the model class?
As I say, I leave to you. Thanks.
(For my future ref c.f. #18668, #15962, ...)
--
Ticket URL: <https://code.djangoproject.com/ticket/30894#comment:7>
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