Opened 13 years ago

Last modified 13 years ago

#16173 closed Cleanup/optimization

manager.get on foreign key fields (related fields) — at Initial Version

Reported by: nitinbhide@… Owned by: nobody
Component: Database layer (models, ORM) Version: dev
Severity: Normal Keywords: manager foreignkey
Cc: fhahn Triage Stage: Accepted
Has patch: no Needs documentation: no
Needs tests: no Patch needs improvement: yes
Easy pickings: yes UI/UX: no

Description

get on ForeignKey field uses manager to query the values.

The code is as given below

# If the related manager indicates that it should be used for

# related fields, respect that.
rel_mgr = self.field.rel.to._default_manager
db = router.db_for_read(self.field.rel.to, instance=instance)
if getattr(rel_mgr, 'use_for_related_fields', False):

rel_obj = rel_mgr.using(db).get(params)


Check the last line 'rel_obj = rel_mgr.using(db).get(params)' for using rel_mgr with multiple databases. rel_mgr.using(db) returns a queryset. If developer has written a Custom Manager class for which 'get' is overriden, then Custom Managers 'get' function will never get called. This results in surprises to the developer. I think this line should changed to

rel_obj = rel_mgr.db_manager(db).get(params)

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