Opened 7 years ago

Last modified 7 years ago

#29021 closed Bug

Weird behavior of foreign key lookup and annotate F expression — at Initial Version

Reported by: Paul Owned by: nobody
Component: Database layer (models, ORM) Version: 1.10
Severity: Normal Keywords: django-model, foreign-key
Cc: Triage Stage: Unreviewed
Has patch: no Needs documentation: no
Needs tests: no Patch needs improvement: no
Easy pickings: no UI/UX: no

Description

class Sentence(Model):
    name = CharField()
    
class Tokens(Model):
    token = CharField()
    sentence = ForeignKey(Sentence, related_name='tokens')
Sentence.objects.annotate(n=Count('tokens', distinct=True)).filter(n=5).filter(tokens__name__in=['se']).annotate(n0=F('tokens')).filter(tokens__name__in=['faire']).annotate(n1=F('tokens')).filter(tokens__name__in=['faire']).annotate(n2=F('tokens')).filter(tokens__name__in=['un']).annotate(n3=F('tokens')).filter(tokens__name__in=['avoir']).annotate(n4=F('tokens'))

Above code generates the following query:

    SELECT "sentence"."id", "sentence"."name" COUNT(DISTINCT "token"."id") AS "n", T3."id" AS "n0", T4."id" AS "n1", T4."id" AS "n2", T6."id" AS "n3", T6."id" AS "n4" FROM "sentence" LEFT OUTER JOIN "token" ON ("sentence"."id" = "token"."sentence_id") INNER JOIN "token" T3 ON ("sentence"."id" = T3."sentence_id") INNER JOIN "token" T4 ON ("sentence"."id" = T4."sentence_id") INNER JOIN "token" T5 ON ("sentence"."id" = T5."sentence_id") INNER JOIN "token" T6 ON ("sentence"."id" = T6."sentence_id") INNER JOIN "token" T7 ON ("sentence"."id" = T7."sentence_id") WHERE (T3."name" IN (se) AND T4."name" IN (faire) AND T5."name" IN (un) AND T6."name" IN (avoir) AND T7."name" IN (faire)) GROUP BY "word_frword"."id", T3."id", T4."id", T6."id" HAVING COUNT(DISTINCT "token"."id") = 5

Why is numbering so strange (starts with T3)? But moreover why n2 is assigned to T4, not T5? Same for n4 and T6. Looks like numbers go by 2.

What I want to accomplish is capture token id on each step of inner join. It works when there are one join, but then it breaks.

Any suggestions?

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