NIKHIL RANE NIKHIL RANE - 1 month ago 16
Python Question

Django: dependencies reference nonexistent parent node

When I run the following command

python manage.py migrate


I receive this error from django so can't step forward in my practice:

Traceback (most recent call last):
File "manage.py", line 10, in <module>
execute_from_command_line(sys.argv)
File "/home/nikhil/testWeb-devEnv/local/lib/python2.7/site-packages/django/core/management/__init__.py", line 385, in execute_from_command_line
utility.execute()
File "/home/nikhil/testWeb-devEnv/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/nikhil/testWeb-devEnv/local/lib/python2.7/site-packages/django/core/management/base.py", line 288, in run_from_argv
self.execute(*args, **options.__dict__)
File "/home/nikhil/testWeb-devEnv/local/lib/python2.7/site-packages/django/core/management/base.py", line 338, in execute
output = self.handle(*args, **options)
File "/home/nikhil/testWeb-devEnv/local/lib/python2.7/site-packages/django/core/management/commands/migrate.py", line 63, in handle
executor = MigrationExecutor(connection, self.migration_progress_callback)
File "/home/nikhil/testWeb-devEnv/local/lib/python2.7/site-packages/django/db/migrations/executor.py", line 17, in __init__
self.loader = MigrationLoader(self.connection)
File "/home/nikhil/testWeb-devEnv/local/lib/python2.7/site-packages/django/db/migrations/loader.py", line 48, in __init__
self.build_graph()
File "/home/nikhil/testWeb-devEnv/local/lib/python2.7/site-packages/django/db/migrations/loader.py", line 241, in build_graph
self.graph.add_dependency(migration, key, parent)
File "/home/nikhil/testWeb-devEnv/local/lib/python2.7/site-packages/django/db/migrations/graph.py", line 42, in add_dependency
raise KeyError("Migration %s dependencies reference nonexistent parent node %r" % (migration, parent))
KeyError: u"Migration testBolt.0001_initial dependencies reference nonexistent parent node (u'delivery_boy', u'0004_auto_20150221_2011')"


How do I solve this problem?

Answer

Solution - 1

Need to remove that reference from testBolt.0001_initial by editing migration file.

Solution - 2

  1. Remove the new changes from the modals and run python manage.py migrate --fake

  2. Now again modify your models with new changes

  3. Run python manage.py makemigrations

  4. And then again run python manage.py migrate

Solution - 3

Remove pyc files from your migrations folder.

Comments