#22611: sqlclear command tries to drop non-existing constraint with ForeignKey
to
self (postgresql)
--------------------------------------------+------------------------
Reporter: valberg | Owner: nobody
Type: Bug | Status: new
Component: Core (Management commands) | Version: 1.7-beta-2
Severity: Normal | Keywords:
Triage Stage: Unreviewed | Has patch: 0
Easy pickings: 0 | UI/UX: 0
--------------------------------------------+------------------------
Having the following model (in an app called test_app):
{{{
class Foo(models.Model):
bar = models.ForeignKey('self')
}}}
The `sqlclear` management command returns:
{{{
$ ./manage.py sqlclear testapp
BEGIN;
ALTER TABLE "testapp_foo" DROP CONSTRAINT "bar_id_refs_id_83e148c5";
DROP TABLE "testapp_foo";
COMMIT;
}}}
Piping this into `psql` results in the following error:
{{{
> ./manage.py sqlclear testapp | psql -U django -h localhost django
BEGIN
ERROR: constraint "bar_id_refs_id_83e148c5" of relation "testapp_foo"
does not exist
ERROR: current transaction is aborted, commands ignored until end of
transaction block
ROLLBACK
}}}
Checking the table in `psql` reveals:
{{{
django=# \d testapp_foo
Table "public.testapp_foo"
Column | Type | Modifiers
--------+---------+----------------------------------------------------------
id | integer | not null default
nextval('testapp_foo_id_seq'::regclass)
bar_id | integer | not null
Indexes:
"testapp_foo_pkey" PRIMARY KEY, btree (id)
"testapp_foo_bar_id" btree (bar_id)
Foreign-key constraints:
"testapp_foo_bar_id_fkey" FOREIGN KEY (bar_id) REFERENCES
testapp_foo(id) DEFERRABLE INITIALLY DEFERRED
Referenced by:
TABLE "testapp_foo" CONSTRAINT "testapp_foo_bar_id_fkey" FOREIGN KEY
(bar_id) REFERENCES testapp_foo(id) DEFERRABLE INITIALLY DEFERRED
}}}
So it seems that the `sqlclear` command generates a different name for the
constraint than it actually is. I'm guessing that postgresql is in charge
of
naming the constraint. At least looking at the output of the `sqlall`
command, there
is no indication of Django doing any naming.
{{{
$ ./manage.py sqlall testapp
BEGIN;
CREATE TABLE "testapp_foo" (
"id" serial NOT NULL PRIMARY KEY,
"bar_id" integer NOT NULL REFERENCES "testapp_foo" ("id") DEFERRABLE
INITIALLY DEFERRED
)
;
CREATE INDEX "testapp_foo_bar_id" ON "testapp_foo" ("bar_id");
COMMIT;
}}}
I've figured out that the "wrongful" naming is done in
`django.db.backends.creation.BaseDatabaseCreation.sql_remove_table_constraints`,
but there my knowledge of Djangos ORM stops :)
It might be worth noting that doing a simple DROP statement drops the
table
just fine. So maybe the ALTER statement isn't necessary?:
{{{
$ echo 'BEGIN; DROP TABLE "testapp_foo"; COMMIT;' | psql -U django -h
localhost django
BEGIN
DROP TABLE
COMMIT
}}}
(I'm using Django 1.7b3 installed with `pip install
git+https://github.com/django/django@stable/1.7.x#egg=Django`, but it is
not listed in the version list.)
--
Ticket URL: <https://code.djangoproject.com/ticket/22611>
Django <https://code.djangoproject.com/>
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