#23983: Cannot Alter order_with_respect_to after there is already data in a
table
----------------------------+--------------------
Reporter: jpulec | Owner: nobody
Type: Bug | Status: new
Component: Migrations | Version: 1.7
Severity: Normal | Keywords:
Triage Stage: Unreviewed | Has patch: 0
Easy pickings: 0 | UI/UX: 0
----------------------------+--------------------
Due to the way that migration operation 'AlterOrderWithRespectTo' is
implemented, it will not set a default for the '_order' column it tries to
create. Because of this, it is not possible to change
'order_with_respect_to' once there is already data in your database, since
the SQL it generates is 'ALTER TABLE "test_app_eggs" ADD COLUMN "_order"
integer NOT NULL;'.
Inital models:
{{{
from django.db import models
# Create your models here.
class Spam(models.Model):
name = models.CharField(max_length=200)
class Eggs(models.Model):
spam = models.ForeignKey('test_app.Spam')
name = models.CharField(max_length=200)
}}}
Then add some data, and change the models to:
{{{
from django.db import models
# Create your models here.
class Spam(models.Model):
name = models.CharField(max_length=200)
class Eggs(models.Model):
spam = models.ForeignKey('test_app.Spam')
name = models.CharField(max_length=200)
class Meta:
order_with_respect_to = 'spam'
}}}
and then make migrations and try to migrate results in the following
traceback:
{{{
(test_project)~/test_project/test_project: $ python manage.py migrate
Operations to perform:
Apply all migrations: admin, test_app, contenttypes, auth, sessions
Running migrations:
Applying test_app.0002_auto_20141211_2202...Traceback (most recent call
last):
File "manage.py", line 10, in <module>
execute_from_command_line(sys.argv)
File "/home/james/.virtualenvs/test_project/local/lib/python2.7/site-
packages/django/core/management/__init__.py", line 385, in
execute_from_command_line
utility.execute()
File "/home/james/.virtualenvs/test_project/local/lib/python2.7/site-
packages/django/core/management/__init__.py", line 377, in execute
self.fetch_command(subcommand).run_from_argv(self.argv)
File "/home/james/.virtualenvs/test_project/local/lib/python2.7/site-
packages/django/core/management/base.py", line 288, in run_from_argv
self.execute(*args, **options.__dict__)
File "/home/james/.virtualenvs/test_project/local/lib/python2.7/site-
packages/django/core/management/base.py", line 338, in execute
output = self.handle(*args, **options)
File "/home/james/.virtualenvs/test_project/local/lib/python2.7/site-
packages/django/core/management/commands/migrate.py", line 160, in handle
executor.migrate(targets, plan, fake=options.get("fake", False))
File "/home/james/.virtualenvs/test_project/local/lib/python2.7/site-
packages/django/db/migrations/executor.py", line 63, in migrate
self.apply_migration(migration, fake=fake)
File "/home/james/.virtualenvs/test_project/local/lib/python2.7/site-
packages/django/db/migrations/executor.py", line 97, in apply_migration
migration.apply(project_state, schema_editor)
File "/home/james/.virtualenvs/test_project/local/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 "/home/james/.virtualenvs/test_project/local/lib/python2.7/site-
packages/django/db/migrations/operations/models.py", line 328, in
database_forwards
field,
File "/home/james/.virtualenvs/test_project/local/lib/python2.7/site-
packages/django/db/backends/schema.py", line 390, in add_field
self.execute(sql, params)
File "/home/james/.virtualenvs/test_project/local/lib/python2.7/site-
packages/django/db/backends/schema.py", line 99, in execute
cursor.execute(sql, params)
File "/home/james/.virtualenvs/test_project/local/lib/python2.7/site-
packages/django/db/backends/utils.py", line 81, in execute
return super(CursorDebugWrapper, self).execute(sql, params)
File "/home/james/.virtualenvs/test_project/local/lib/python2.7/site-
packages/django/db/backends/utils.py", line 65, in execute
return self.cursor.execute(sql, params)
File "/home/james/.virtualenvs/test_project/local/lib/python2.7/site-
packages/django/db/utils.py", line 94, in __exit__
six.reraise(dj_exc_type, dj_exc_value, traceback)
File "/home/james/.virtualenvs/test_project/local/lib/python2.7/site-
packages/django/db/backends/utils.py", line 65, in execute
return self.cursor.execute(sql, params)
django.db.utils.IntegrityError: column "_order" contains null values
}}}
--
Ticket URL: <https://code.djangoproject.com/ticket/23983>
Django <https://code.djangoproject.com/>
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