CODEWITHSUNDEEP
pythondjangodjango-migrationsdjango-database
yarsanich
yarsanich

Reputation: 304

django.db.migrations.exceptions.CircularDependencyError

I have a problem with Django migrations on empty DB. When I want to migrate I have a circular dependency error. Circular dependency error between two apps that related by foreign keys

/firstapp/models.py 

class Person(models.Model):
   ...


class Doctor(Person):
    hospital = models.ForeignKey('hospital.Hospital', on_delete=models.SET_NULL, null=True, default=None,blank = True)
    ...

class Patient(Person):
    doctor = models.ForeignKey('Doctor', on_delete=models.SET_NULL, null=True, default=None)

/secondapp/models.py

class Hospital(models.Model):
    ...
    main_doctor = models.ForeignKey('authoriz.Doctor', on_delete=models.SET_NULL, null=True,verbose_name="Main Doctor")
    calendar = models.ForeignKey('schedule.Calendar',verbose_name="calendar",null = True)
    ...

class Seat(models.Model):
    hospital = models.ForeignKey('Hospital', on_delete=models.CASCADE)
    ...

After

python manage.py migrate

Traceback

Traceback (most recent call last):
  File "manage.py", line 22, in <module>
    execute_from_command_line(sys.argv)
  File "/home/user/project/lib/python3.5/site-packages/django/core/management/__init__.py", line 367, in execute_from_command_line
    utility.execute()
  File "/home/user/project/lib/python3.5/site-packages/django/core/management/__init__.py", line 359, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/home/user/project/lib/python3.5/site-packages/django/core/management/base.py", line 305, in run_from_argv
    self.execute(*args, **cmd_options)
  File "/home/user/project/lib/python3.5/site-packages/django/core/management/base.py", line 356, in execute
    output = self.handle(*args, **options)
  File "/home/user/project/lib/python3.5/site-packages/django/core/management/commands/migrate.py", line 136, in handle
    plan = executor.migration_plan(targets)
  File "/home/user/project/lib/python3.5/site-packages/django/db/migrations/executor.py", line 60, in migration_plan
    for migration in self.loader.graph.forwards_plan(target):
  File "/home/user/project/lib/python3.5/site-packages/django/db/migrations/graph.py", line 280, in forwards_plan
    self.ensure_not_cyclic(target, lambda x: (parent.key for parent in self.node_map[x].parents))
  File "/home/user/project/lib/python3.5/site-packages/django/db/migrations/graph.py", line 370, in ensure_not_cyclic
    raise CircularDependencyError(", ".join("%s.%s" % n for n in cycle))
django.db.migrations.exceptions.CircularDependencyError: authoriz.0001_initial, hospital.0001_initial

Thanks for help.

Upvotes: 17

Views: 18410

Answers (4)

Asif
Asif

Reputation: 83

  1. Delete your existing virtual environment and create a new one.
  2. In your models files, comment out all ForeignKey fields.
  3. Run migrations and migrate
  4. Uncomment the ForeignKey fields you commented
  5. Again run migrations and migrate

Upvotes: 0

Varun Sharma
Varun Sharma

Reputation: 80

Like you might have defined them as something below:

new_field = models.ForeignKey(ForeignModel, ...)

Instead do this:

new_field = models.ForeignKey("ForeignModel", ...)

Upvotes: 0

Josue Ttito
Josue Ttito

Reputation: 23

Should be useful if you add your Calendar model. However don't use the inheritance without abstract modal.

class Person(models.Model):
    ...

    class Meta:
        abstract = True

Upvotes: 0

Alasdair
Alasdair

Reputation: 308939

Temporarily comment out foreign keys to break the circular dependency. It looks like you could do this by commenting out Hospital.doctor. Remove the existing migrations and run makemigrations to recreate them.

Finally, uncomment the foreign keys, and run makemigrations again. You should end up with migrations without any circular dependencies.

Upvotes: 29

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