#30382: force_insert flag is not passed when saving parents on inherited models.
-------------------------------------+-------------------------------------
Reporter: Phill Tornroth | Owner: Akash
| Kumar Sen
Type: Bug | Status: assigned
Component: Database layer | Version: dev
(models, ORM) |
Severity: Normal | Resolution:
Keywords: | Triage Stage: Accepted
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
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Comment (by Natalia Bidart):
Thank you Akash, your comment helped me reproduce the reported issue. In
summary, a Parent model with at least two fields, `id` and `name` for
example, would generate these queries for
`ChildModel(id=1).save(force_insert=True)`:
{{{
1. UPDATE "ticket_30382_parentmodel" SET "name" = '' WHERE
"ticket_30382_parentmodel"."id" = 1
2. INSERT INTO "ticket_30382_parentmodel" ("id", "name") VALUES (1, '')
3. INSERT INTO "ticket_30382_childmodel" ("parentmodel_ptr_id") VALUES (1)
}}}
I also added a test for the alternate code:
{{{
parent = ParentModel.objects.create(id=1)
ChildModel.objects.create(parentmodel_ptr=parent)
}}}
which generates these queries:
{{{
1. INSERT INTO "ticket_30382_parentmodel" ("id", "name") VALUES (1, '')
2. UPDATE "ticket_30382_parentmodel" SET "name" = '' WHERE
"ticket_30382_parentmodel"."id" = 1
3. INSERT INTO "ticket_30382_childmodel" ("parentmodel_ptr_id") VALUES (1)
}}}
When testing this same code with the **proposed PR**, **the first case
gets fixed as expected**, these are the queries I get for the reported
code (so YEY):
{{{
1. INSERT INTO "ticket_30382_parentmodel" ("id", "name") VALUES (1, '')
2. INSERT INTO "ticket_30382_childmodel" ("parentmodel_ptr_id") VALUES (1)
}}}
**But** for the second code snippet (create parent and then create child)
I get an **extra query** (so HUM). Is this expected? I wouldn't think
so...
{{{
1. INSERT INTO "ticket_30382_parentmodel" ("id", "name") VALUES (1, '')
2. UPDATE "ticket_30382_parentmodel" SET "name" = '' WHERE
"ticket_30382_parentmodel"."id" = 1
3. SELECT 1 AS "a" FROM "ticket_30382_childmodel" WHERE
"ticket_30382_childmodel"."parentmodel_ptr_id" = 1 LIMIT 1
4. INSERT INTO "ticket_30382_childmodel" ("parentmodel_ptr_id") VALUES (1)
}}}
--
Ticket URL: <https://code.djangoproject.com/ticket/30382#comment:11>
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