[Django] #22761: Migrating from an auto to natural key with foreign model and 'to' FK
Django
-------------------------------+------------------------
Reporter: smeatonj | Owner: nobody
Type: Uncategorized | Status: new
Component: Uncategorized | Version: 1.7-beta-2
Severity: Normal | Keywords: migrations
Triage Stage: Unreviewed | Has patch: 0
Easy pickings: 0 | UI/UX: 0
-------------------------------+------------------------
I've run into issues with Postgres and Oracle (so I'd assume other
backends are affected) not being able to migrate a model from an auto
primary key to a natural primary key, where another model has a foreign
key that points at the natural.
{{{
class Recording(models.Model):
some_key = models.PositiveIntegerField(unique=True)
class Tag(models.Model):
recording = models.ForeignKey(Recording, to_field='some_key')
(scratchpad)smeatonj ~/Development/scratchpad $ ./manage.py makemigrations
Migrations for 'migrationstest':
0001_initial.py:
- Create model Recording
- Create model Tag
class Migration(migrations.Migration):
dependencies = [
]
operations = [
migrations.CreateModel(
name='Recording',
fields=[
('id', models.AutoField(verbose_name='ID',
serialize=False, auto_created=True, primary_key=True)),
('some_key', models.PositiveIntegerField(unique=True)),
],
options={
},
bases=(models.Model,),
),
migrations.CreateModel(
name='Tag',
fields=[
('id', models.AutoField(verbose_name='ID',
serialize=False, auto_created=True, primary_key=True)),
('recording',
models.ForeignKey(to='migrationstest.Recording', to_field=b'some_key')),
],
options={
},
bases=(models.Model,),
),
]
(scratchpad)smeatonj ~/Development/scratchpad $ ./manage.py migrate
Operations to perform:
Synchronize unmigrated apps: sessions, admin, scratch, debug_toolbar,
sites, auth, aggregation, contenttypes, django_extensions
Apply all migrations: migrationstest
Synchronizing apps without migrations:
Creating tables...
Installing custom SQL...
Installing indexes...
Running migrations:
Applying migrationstest.0001_initial... FAKED
(scratchpad)smeatonj ~/Development/scratchpad $
}}}
Now we change the main model to use a natural key, and remove the `to`
directive of the foreign key:
{{{
# change to natural key
class Recording(models.Model):
some_key = models.PositiveIntegerField(primary_key=True)
class Tag(models.Model):
recording = models.ForeignKey(Recording)
(scratchpad)smeatonj ~/Development/scratchpad $ ./manage.py makemigrations
Migrations for 'migrationstest':
0002_auto_20140604_0806.py:
- Remove field id from recording
- Alter field some_key on recording
class Migration(migrations.Migration):
dependencies = [
('migrationstest', '0001_initial'),
]
operations = [
migrations.RemoveField(
model_name='recording',
name='id',
),
migrations.AlterField(
model_name='recording',
name='some_key',
field=models.PositiveIntegerField(serialize=False,
primary_key=True),
),
]
(scratchpad)smeatonj ~/Development/scratchpad $ ./manage.py migrate
Operations to perform:
Synchronize unmigrated apps: sessions, admin, scratch, debug_toolbar,
sites, auth, aggregation, contenttypes, django_extensions
Apply all migrations: migrationstest
Synchronizing apps without migrations:
Creating tables...
Installing custom SQL...
Installing indexes...
Running migrations:
Applying migrationstest.0002_auto_20140604_0806...Traceback (most recent
call last):
File "./manage.py", line 9, in <module>
execute_from_command_line(sys.argv)
File "/Users/smeatonj/Development/.virtualenvs/scratchpad/lib/python2.7
/site-packages/django/core/management/__init__.py", line 427, in
execute_from_command_line
utility.execute()
File "/Users/smeatonj/Development/.virtualenvs/scratchpad/lib/python2.7
/site-packages/django/core/management/__init__.py", line 419, in execute
self.fetch_command(subcommand).run_from_argv(self.argv)
File "/Users/smeatonj/Development/.virtualenvs/scratchpad/lib/python2.7
/site-packages/django/core/management/base.py", line 288, in run_from_argv
self.execute(*args, **options.__dict__)
File "/Users/smeatonj/Development/.virtualenvs/scratchpad/lib/python2.7
/site-packages/django/core/management/base.py", line 337, in execute
output = self.handle(*args, **options)
File "/Users/smeatonj/Development/.virtualenvs/scratchpad/lib/python2.7
/site-packages/django/core/management/commands/migrate.py", line 146, in
handle
executor.migrate(targets, plan, fake=options.get("fake", False))
File "/Users/smeatonj/Development/.virtualenvs/scratchpad/lib/python2.7
/site-packages/django/db/migrations/executor.py", line 62, in migrate
self.apply_migration(migration, fake=fake)
File "/Users/smeatonj/Development/.virtualenvs/scratchpad/lib/python2.7
/site-packages/django/db/migrations/executor.py", line 96, in
apply_migration
migration.apply(project_state, schema_editor)
File "/Users/smeatonj/Development/.virtualenvs/scratchpad/lib/python2.7
/site-packages/django/db/migrations/migration.py", line 107, in apply
operation.database_forwards(self.app_label, schema_editor,
project_state, new_state)
File "/Users/smeatonj/Development/.virtualenvs/scratchpad/lib/python2.7
/site-packages/django/db/migrations/operations/fields.py", line 132, in
database_forwards
schema_editor.alter_field(from_model, from_field, to_field)
File "/Users/smeatonj/Development/.virtualenvs/scratchpad/lib/python2.7
/site-packages/django/db/backends/schema.py", line 508, in alter_field
"name": constraint_name,
File "/Users/smeatonj/Development/.virtualenvs/scratchpad/lib/python2.7
/site-packages/django/db/backends/schema.py", line 98, in execute
cursor.execute(sql, params)
File "/Users/smeatonj/Development/.virtualenvs/scratchpad/lib/python2.7
/site-packages/django/db/backends/utils.py", line 81, in execute
return super(CursorDebugWrapper, self).execute(sql, params)
File "/Users/smeatonj/Development/.virtualenvs/scratchpad/lib/python2.7
/site-packages/django/db/backends/utils.py", line 65, in execute
return self.cursor.execute(sql, params)
File "/Users/smeatonj/Development/.virtualenvs/scratchpad/lib/python2.7
/site-packages/django/db/utils.py", line 94, in __exit__
six.reraise(dj_exc_type, dj_exc_value, traceback)
File "/Users/smeatonj/Development/.virtualenvs/scratchpad/lib/python2.7
/site-packages/django/db/backends/utils.py", line 65, in execute
return self.cursor.execute(sql, params)
django.db.utils.InternalError: cannot drop constraint
migrationstest_recording_some_key_key on table migrationstest_recording
because other objects depend on it
DETAIL: constraint b25f2749e675737f4ae4891ed60d858c on table
migrationstest_tag depends on index migrationstest_recording_some_key_key
HINT: Use DROP ... CASCADE to drop the dependent objects too.
}}}
It blows up in Oracle too:
{{{
Traceback (most recent call last):
File "/vagrant/venv/lib/python3.3/site-
packages/django/db/backends/utils.py", line 65, in execute
return self.cursor.execute(sql, params)
File "/vagrant/venv/lib/python3.3/site-
packages/django/db/backends/oracle/base.py", line 884, in execute
return self.cursor.execute(query, self._param_generator(params))
cx_Oracle.DatabaseError: ORA-02273: this unique/primary key is referenced
by some foreign keys
The above exception was the direct cause of the following exception:
Traceback (most recent call last):
File "./manage.py", line 10, in <module>
execute_from_command_line(sys.argv)
File "/vagrant/venv/lib/python3.3/site-
packages/django/core/management/__init__.py", line 427, in
execute_from_command_line
utility.execute()
File "/vagrant/venv/lib/python3.3/site-
packages/django/core/management/__init__.py", line 419, in execute
self.fetch_command(subcommand).run_from_argv(self.argv)
File "/vagrant/venv/lib/python3.3/site-
packages/django/core/management/base.py", line 288, in run_from_argv
self.execute(*args, **options.__dict__)
File "/vagrant/venv/lib/python3.3/site-
packages/django/core/management/base.py", line 337, in execute
output = self.handle(*args, **options)
File "/vagrant/venv/lib/python3.3/site-
packages/django/core/management/commands/migrate.py", line 146, in handle
executor.migrate(targets, plan, fake=options.get("fake", False))
File "/vagrant/venv/lib/python3.3/site-
packages/django/db/migrations/executor.py", line 62, in migrate
self.apply_migration(migration, fake=fake)
File "/vagrant/venv/lib/python3.3/site-
packages/django/db/migrations/executor.py", line 96, in apply_migration
migration.apply(project_state, schema_editor)
File "/vagrant/venv/lib/python3.3/site-
packages/django/db/migrations/migration.py", line 107, in apply
operation.database_forwards(self.app_label, schema_editor,
project_state, new_state)
File "/vagrant/venv/lib/python3.3/site-
packages/django/db/migrations/operations/fields.py", line 132, in
database_forwards
schema_editor.alter_field(from_model, from_field, to_field)
File "/vagrant/venv/lib/python3.3/site-
packages/django/db/backends/oracle/schema.py", line 49, in alter_field
super(DatabaseSchemaEditor, self).alter_field(model, old_field,
new_field, strict)
File "/vagrant/venv/lib/python3.3/site-
packages/django/db/backends/schema.py", line 508, in alter_field
"name": constraint_name,
File "/vagrant/venv/lib/python3.3/site-
packages/django/db/backends/schema.py", line 98, in execute
cursor.execute(sql, params)
File "/vagrant/venv/lib/python3.3/site-
packages/django/db/backends/utils.py", line 81, in execute
return super(CursorDebugWrapper, self).execute(sql, params)
File "/vagrant/venv/lib/python3.3/site-
packages/django/db/backends/utils.py", line 65, in execute
return self.cursor.execute(sql, params)
File "/vagrant/venv/lib/python3.3/site-packages/django/db/utils.py",
line 94, in __exit__
six.reraise(dj_exc_type, dj_exc_value, traceback)
File "/vagrant/venv/lib/python3.3/site-packages/django/utils/six.py",
line 549, in reraise
raise value.with_traceback(tb)
File "/vagrant/venv/lib/python3.3/site-
packages/django/db/backends/utils.py", line 65, in execute
return self.cursor.execute(sql, params)
File "/vagrant/venv/lib/python3.3/site-
packages/django/db/backends/oracle/base.py", line 884, in execute
return self.cursor.execute(query, self._param_generator(params))
django.db.utils.DatabaseError: ORA-02273: this unique/primary key is
referenced by some foreign keys
}}}
--
Ticket URL: <https://code.djangoproject.com/ticket/22761>
Django <https://code.djangoproject.com/>
The Web framework for perfectionists with deadlines.
Django
Reporter: smeatonj | Owner: nobody
Type: Uncategorized | Status: new
Component: Uncategorized | Version: 1.7-beta-2
Keywords: migrations | Triage Stage: Unreviewed
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
Changes (by smeatonj):
* needs_better_patch: => 0
* needs_tests: => 0
* needs_docs: => 0
Comment:
A few extra notes:
- switching the operations around (Alter then Remove) has the same problem
- leaving the to="key" doesn't change anything
--
Ticket URL: <https://code.djangoproject.com/ticket/22761#comment:1>
Django
Reporter: smeatonj | Owner: nobody
Type: Uncategorized | Status: new
Component: Uncategorized | Version: 1.7-beta-2
Keywords: migrations | Triage Stage: Unreviewed
Easy pickings: 0 | UI/UX: 0
Comment (by andrewgodwin):
It looks like the primary issue here is the ForeignKey repointing not
working correctly with the to_field argument. Not categorising as RB for
now as it's a lesser-used feature and nothing in migrations is technically
a regression.
--
Ticket URL: <https://code.djangoproject.com/ticket/22761#comment:2>
Django
Reporter: smeatonj | Owner: nobody
Type: Bug | Status: new
Component: Migrations | Version: 1.7-beta-2
Severity: Normal | Resolution:
Keywords: migrations | Triage Stage: Accepted
Has patch: 0 | Needs documentation: 0
Easy pickings: 0 | UI/UX: 0
Changes (by timo):
* type: Uncategorized => Bug
* component: Uncategorized => Migrations
* stage: Unreviewed => Accepted
--
Ticket URL: <https://code.djangoproject.com/ticket/22761#comment:3>
Django
Reporter: smeatonj | Owner: nobody
Type: Bug | Status: new
Component: Migrations | Version: 1.7
Keywords: migrations | Triage Stage: Accepted
Has patch: 0 | Needs documentation: 0
Easy pickings: 0 | UI/UX: 0
Changes (by timgraham):
* version: 1.7-beta-2 => 1.7
--
Ticket URL: <https://code.djangoproject.com/ticket/22761#comment:4>