#31834 closed Bug (duplicate)
Cannot sqlmigrate on Django migrations that change unique_together
Reported by: | Brіаn Lаі | Owned by: | nobody |
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Component: | Migrations | Version: | 3.0 |
Severity: | Normal | Keywords: | sqlmigrate |
Cc: | Triage Stage: | Unreviewed | |
Has patch: | no | Needs documentation: | no |
Needs tests: | no | Patch needs improvement: | no |
Easy pickings: | no | UI/UX: | no |
Description (last modified by )
Somewhat similar to #26624, but forward sqlmigrate, reproduced on Django 3.0.8 and Postgres 10.x.
If a model has a unique_together of
unique_together = [ (a, b) ]
and it becomes
unique_together = [ (a, b, c) ]
, although the makemigrations command successfully generates a new migration with the corresponding AlterUniqueTogether() operation, the migration cannot be inspected with the sqlmigrate command.
Reproduce bug with the following (the project may also be attached)
class Model1(models.Model): id = models.IntegerField(primary_key=True) name = models.CharField(max_length=255, unique=True) class Model2(models.Model): id = models.IntegerField(primary_key=True) link_id = models.CharField(max_length=255) settings = models.ForeignKey(Model1, on_delete=models.CASCADE) class Model3(models.Model): id = models.IntegerField(primary_key=True) order = models.IntegerField() model_2 = models.ForeignKey(Model2, on_delete=models.CASCADE) direct = models.BooleanField(default=True) class Meta: unique_together = [ ('model_2', 'order') # To get the bug, change this to ('model_2', 'order', 'direct') and sqlmigrate the migration that this creates. ]
The error shown in the terminal is:
Traceback (most recent call last): File "manage.py", line 22, in <module> execute_from_command_line(sys.argv) File "/lib/python3.6/site-packages/django/core/management/__init__.py", line 401, in execute_from_command_line utility.execute() File "/lib/python3.6/site-packages/django/core/management/__init__.py", line 395, in execute self.fetch_command(subcommand).run_from_argv(self.argv) File "/lib/python3.6/site-packages/django/core/management/base.py", line 328, in run_from_argv self.execute(*args, **cmd_options) File "/lib/python3.6/site-packages/django/core/management/commands/sqlmigrate.py", line 30, in execute return super().execute(*args, **options) File "/lib/python3.6/site-packages/django/core/management/base.py", line 369, in execute output = self.handle(*args, **options) File "/lib/python3.6/site-packages/django/core/management/commands/sqlmigrate.py", line 65, in handle sql_statements = executor.collect_sql(plan) File "/lib/python3.6/site-packages/django/db/migrations/executor.py", line 225, in collect_sql state = migration.apply(state, schema_editor, collect_sql=True) File "/lib/python3.6/site-packages/django/db/migrations/migration.py", line 124, in apply operation.database_forwards(self.app_label, schema_editor, old_state, project_state) File "/lib/python3.6/site-packages/django/db/migrations/operations/models.py", line 525, in database_forwards getattr(new_model._meta, self.option_name, set()), File "/lib/python3.6/site-packages/django/db/backends/base/schema.py", line 380, in alter_unique_together self._delete_composed_index(model, fields, {'unique': True}, self.sql_delete_unique) File "/lib/python3.6/site-packages/django/db/backends/base/schema.py", line 414, in _delete_composed_index ", ".join(columns), ValueError: Found wrong number (0) of constraints for bar_model3(model_2, order)
Attachments (1)
Change History (5)
by , 4 years ago
Attachment: | foo.tar.gz added |
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comment:1 by , 4 years ago
Description: | modified (diff) |
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comment:2 by , 4 years ago
Description: | modified (diff) |
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comment:3 by , 4 years ago
Component: | Database layer (models, ORM) → Migrations |
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Resolution: | → duplicate |
Status: | new → closed |
I think we can mark this as a duplicate of #26624, because they have the same cause. In both scenarios a constraint doesn't exist in the database and cannot be introspected, sqlmigrate
works properly if you first apply a migration which adds a constraint.
comment:4 by , 4 years ago
I guess so. However you choose to triage and/or fix the item, I hope I am providing additional context by saying this bug can be reproduced with SQLite, whereas #26624 claims they could not.
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