Opened 6 years ago

Closed 6 years ago

#11899 closed (invalid)

QuerySet - filter through related objects

Reported by: fgrzadkowski Owned by: nobody
Component: Documentation Version: 1.1
Severity: Keywords:
Cc: Triage Stage: Unreviewed
Has patch: no Needs documentation: no
Needs tests: no Patch needs improvement: no
Easy pickings: UI/UX:

Description

Lets say we have models like:

class A(models.Model):
    pass

class B(models.Model):
    t = models.CharField(max_length=100)
    a = models.ForeignKey('A')

I've found out, that the following query is working:

A.objects.filter(b__t='1').filter(b__t='2')

which returns those As that have at least one B with t='1' AND at
least one B with t='2'. The underlying query looks like this:

SELECT "search_test_a"."id"
FROM "search_test_a"
INNER JOIN "search_test_b" ON ("search_test_a"."id" = "search_test_b"."a_id")
INNER JOIN "search_test_b" T3 ON ("search_test_a"."id" = T3."a_id")
WHERE ("search_test_b"."t" = E'1'  AND T3."t" = E'2' ) LIMIT 21

So we have two thigns which are not documented (or I can't find it):

  • possibility to filter like above
  • if we set related_name="bs" in B for field a, then it affect not only foreignkey manager in A, but also filter function ( .filter(bs__t='1' )

Or maybe its all not official features? But if not then it should be, because it's very useful :)

Change History (1)

comment:1 Changed 6 years ago by fgrzadkowski

  • Needs documentation unset
  • Needs tests unset
  • Patch needs improvement unset
  • Resolution set to invalid
  • Status changed from new to closed
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