Opened 17 years ago
Closed 16 years ago
#7290 closed (duplicate)
filter
Reported by: | Owned by: | nobody | |
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Component: | Database layer (models, ORM) | Version: | dev |
Severity: | Keywords: | qsrf-cleanup | |
Cc: | ondrej.kohout@… | Triage Stage: | Unreviewed |
Has patch: | no | Needs documentation: | no |
Needs tests: | no | Patch needs improvement: | no |
Easy pickings: | no | UI/UX: | no |
Description
When using OR operation on two Q objects, witch are both filtering on the same table, it leaves out one condition in WHERE clause.
Given this model and the filter, django will query database for:
SELECT "a_team"."id", "a_team"."name" FROM "a_team" LEFT OUTER JOIN "a_match" ON ("a_team"."id" = "a_match"."home_team_id") LEFT OUTER JOIN "a_match" T4 ON ("a_team"."id" = T4."guest_team_id") WHERE "a_match"."round_id" = 1;
But it should use:
SELECT "a_team"."id", "a_team"."name" FROM "a_team" LEFT OUTER JOIN "a_match" ON ("a_team"."id" = "a_match"."home_team_id") LEFT OUTER JOIN "a_match" T4 ON ("a_team"."id" = T4."guest_team_id") WHERE "a_match"."round_id" = 1 OR T4.round_id = 1;
Mind the difference in the where clause. Even though T4 is just alias for 'a_match' table, and both conditions are comparing 'round_id' for the same value (1), it's important to use both.
from django.db import models class Team(models.Model): name = models.CharField(max_length=100) class Round(models.Model): name = models.CharField(max_length=100) class Match(models.Model): home_team = models.ForeignKey(Team, related_name='home_team_set') guest_team = models.ForeignKey(Team, related_name='guest_team_set') round = models.ForeignKey(Round) __test__ = {'bug': """ # Data init >>> r = Round(name='round 1') >>> r.save() >>> t1 = Team(name='Cze') >>> t1.save() >>> t2 = Team(name='USA') >>> t2.save() >>> Match(home_team=t1, guest_team=t2, round=r).save() # Get teams with matches in round 'r' >>> result = Team.objects.filter(models.Q(home_team_set__round=r) | models.Q(guest_team_set__round=r)) >>> len(result) 2 """}
Change History (3)
comment:1 by , 16 years ago
Keywords: | qsrf-cleanup added |
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comment:2 by , 16 years ago
comment:3 by , 16 years ago
Resolution: | → duplicate |
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Status: | new → closed |
Indeed; another dup of #7125.
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I think this is the same is #7125.