Django: dependencies reference nonexistent parent

问题:

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?

回答1:

Solution - 1

Remove pyc files from your migrations folder.

Solution - 2

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

Solution - 3

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

回答2:

I had a similar case, running django in windows in a virtual env. In my case the missing dependency was 0001_initial - which was definitely there in the migration folder.

The 'solution' was to remove the pyc files and do another migrate attempt.

回答3:

I had the same problem. In my case, because I played with migrations manually, I forgot to create __init__.py inside of migrations folder.

回答4:

Make sure that you have activated your virtual environment.

回答5:

In my case, I had the .py extension in the dependency module name, like this:

dependencies = [
    ('dashboard', '0003_auto_20181024_0603.py'),
    ('auth', '__latest__'),
    ('contenttypes', '__latest__'),
]

I removed the .py, changing it to this

    ('dashboard', '0003_auto_20181024_0603')

and that fixed it.

回答6:

There could be some migration files remaining in the app when you tried the migrate command. First remove all migrations directories from all the modules. For other cases Nikhil Rane has covered it all.

回答7:

I tried NIKHIL's solutions with no luck. What did work for me was:

• Removing my virtual environment
• Deleting the migration __pycache__ folders
• Deleting old migrations
• Recreating my virtual environment
• Running migrations

回答8:

1. run python manage.py migrate --fake

2. Run python manage.py makemigrations

3. And then again run python manage.py migrate

this fixed mine smoothly

回答9:

KeyError: u"Migration testBolt.0001_initial dependencies reference nonexistent parent node (u'delivery_boy', u'0004_auto_20150221_2011')"

Remove

testBolt.0001_initial

then run migrate again

回答10:

Go to folder testBolt -> migrations and remove 0001_initial py and pyc files.