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.
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.