oracle: case mixup causes ORA-00918: column ambiguously defined error

[Charlie.Tang@…]

a model's fields, which have a common related model, led to the issue.

Here is an example:

class Institution(models.Model):
    name = models.CharField('full name', max_length=50)

class Personel(models.Model):
    institution = models.ForeignKey(Institution)

class Protocol(models.Model):
    Institution = models.ForeignKey('Institution', blank=True, null=True)

class StudyAssignment(models.Model):
    personel = models.ForeignKey(Personel)
    protocol = models.ForeignKey(Protocol)

which generated sql

SELECT * 
FROM 
(   SELECT ROWNUM AS "_RN", "_SUB".* 
    FROM 
    (   SELECT "STUDY_ASSIGNMENT"."ID", "STUDY_ASSIGNMENT"."PERSONEL_ID", "STUDY_ASSIGNMENT"."PROTOCOL_ID", "PERSONEL"."ID" AS Col3
              , "PERSONEL"."INSTITUTION_ID"
              , "INSTITUTION"."ID" AS Col5, "INSTITUTION"."NAME", "PROTOCOL"."ID" AS Col7
              , "PROTOCOL"."INSTITUTION_ID"
              , T5."ID" AS Col9, T5."NAME" AS Col10 
        FROM "STUDY_ASSIGNMENT" 
              INNER JOIN "PERSONEL" ON ("STUDY_ASSIGNMENT"."PERSONEL_ID" = "PERSONEL"."ID") 
              INNER JOIN "INSTITUTION" ON ("PERSONEL"."INSTITUTION_ID" = "INSTITUTION"."ID") 
              INNER JOIN "PROTOCOL" ON ("STUDY_ASSIGNMENT"."PROTOCOL_ID" = "PROTOCOL"."ID") 
            INNER JOIN "INSTITUTION" T5 ON ("PROTOCOL"."INSTITUTION_ID" = T5."ID") 
        ORDER BY "STUDY_ASSIGNMENT"."ID" DESC
    ) "_SUB"
    WHERE ROWNUM <= 21
)
WHERE "_RN" > 0;

To call model StudyAssignment through django admin. Both "PERSONEL"."INSTITUTION_ID" and "PROTOCOL"."INSTITUTION_ID" led to the issue.

[Charlie.Tang@…]

Fixed the issues through changing the field name Institution of class Protocol to lower case

[Mariusz Felisiak]

I couldn't reproduce this issue on stable/1.7.x -> master. I think we can add a test and close this ticket.

[Mariusz Felisiak]

​PR with test.

[Shai Berger]

Added some cosmetic comments on the PR, but it's mostly good to go.

[GitHub <noreply@…>]

In aad1833f:

Refs #20487 -- Added test for querying mixed case fields with common related model.

Thanks Shai Berger for the review.