Django Migration Problem with URL Configuration - django

Question

When we started our Django project we created migrations and migrated, but now, when we want to alter the data model and run makemigrations we get a large error message (see below). After tracing back the message I discovered that when I comment the path('', include('quizarchiv.urls')), lie while running migrations everything is fine. So I guess that I got two questions:
Why does this workaround work (at least for creating the migrations)?
How do we adjust our project to work with migrations again?
This is the part of our models.py (it's rather long):
class questioncategory(models.Model):
cat_id = models.AutoField(primary_key=True)
cat_name = models.CharField(max_length=255, unique=True)
class question(models.Model):
q_id = models.AutoField(primary_key=True)
q_title = models.CharField(max_length=255, unique=True)
q_question = models.CharField(max_length=1000)
f_kat = models.ForeignKey(questioncategory, on_delete=models.PROTECT)
Full error message:
COMPUTER:FOLDER USERNAME$ python3 manage.py migrate
Traceback (most recent call last):
File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/django/db/backends/utils.py", line 84, in _execute
return self.cursor.execute(sql, params)
File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/django/db/backends/sqlite3/base.py", line 383, in execute
return Database.Cursor.execute(self, query, params)
sqlite3.OperationalError: no such table: questioncategory
The above exception was the direct cause of the following exception:
Traceback (most recent call last):
File "manage.py", line 21, in <module>
main()
File "manage.py", line 17, in main
execute_from_command_line(sys.argv)
File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/django/core/management/__init__.py", line 381, in execute_from_command_line
utility.execute()
File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/django/core/management/__init__.py", line 375, in execute
self.fetch_command(subcommand).run_from_argv(self.argv)
File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/django/core/management/base.py", line 323, in run_from_argv
self.execute(*args, **cmd_options)
File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/django/core/management/base.py", line 361, in execute
self.check()
File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/django/core/management/base.py", line 390, in check
include_deployment_checks=include_deployment_checks,
File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/django/core/management/commands/migrate.py", line 65, in _run_checks
issues.extend(super()._run_checks(**kwargs))
File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/django/core/management/base.py", line 377, in _run_checks
return checks.run_checks(**kwargs)
File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/django/core/checks/registry.py", line 72, in run_checks
new_errors = check(app_configs=app_configs)
File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/django/core/checks/urls.py", line 40, in check_url_namespaces_unique
all_namespaces = _load_all_namespaces(resolver)
File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/django/core/checks/urls.py", line 57, in _load_all_namespaces
url_patterns = getattr(resolver, 'url_patterns', [])
File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/django/utils/functional.py", line 80, in __get__
res = instance.__dict__[self.name] = self.func(instance)
File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/django/urls/resolvers.py", line 571, in url_patterns
patterns = getattr(self.urlconf_module, "urlpatterns", self.urlconf_module)
File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/django/utils/functional.py", line 80, in __get__
res = instance.__dict__[self.name] = self.func(instance)
File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/django/urls/resolvers.py", line 564, in urlconf_module
return import_module(self.urlconf_name)
File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/importlib/__init__.py", line 127, in import_module
return _bootstrap._gcd_import(name[level:], package, level)
File "<frozen importlib._bootstrap>", line 1006, in _gcd_import
File "<frozen importlib._bootstrap>", line 983, in _find_and_load
File "<frozen importlib._bootstrap>", line 967, in _find_and_load_unlocked
File "<frozen importlib._bootstrap>", line 677, in _load_unlocked
File "<frozen importlib._bootstrap_external>", line 728, in exec_module
File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
File "/Users/USERNAME/PROJECTPATH/web/web/urls.py", line 22, in <module>
path('', include('quiz.urls')),
File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/django/urls/conf.py", line 34, in include
urlconf_module = import_module(urlconf_module)
File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/importlib/__init__.py", line 127, in import_module
return _bootstrap._gcd_import(name[level:], package, level)
File "<frozen importlib._bootstrap>", line 1006, in _gcd_import
File "<frozen importlib._bootstrap>", line 983, in _find_and_load
File "<frozen importlib._bootstrap>", line 967, in _find_and_load_unlocked
File "<frozen importlib._bootstrap>", line 677, in _load_unlocked
File "<frozen importlib._bootstrap_external>", line 728, in exec_module
File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
File "/Users/USERNAME/PROJECTPATH/web/quizarchiv/urls.py", line 2, in <module>
from . import views
File "/Users/USERNAME/PROJECTPATH/web/quizarchiv/views.py", line 20, in <module>
from .forms import ErstelleFrage, ErstelleSession, ErstelleAsset, ErstelleHinweis, ErstelleTeam, ErstelleKategorie
File "/Users/USERNAME/PROJECTPATH/web/quizarchiv/forms.py", line 8, in <module>
class ErstelleFrage(forms.Form):
File "/Users/USERNAME/PROJECTPATH/web/quizarchiv/forms.py", line 12, in ErstelleFrage
f_kategorie = forms.ChoiceField(choices=[(kat.kategorie_id, kat.k_name) for kat in FrageKategorie.objects.all()], label="Kategorie")
File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/django/db/models/query.py", line 274, in __iter__
self._fetch_all()
File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/django/db/models/query.py", line 1242, in _fetch_all
self._result_cache = list(self._iterable_class(self))
File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/django/db/models/query.py", line 55, in __iter__
results = compiler.execute_sql(chunked_fetch=self.chunked_fetch, chunk_size=self.chunk_size)
File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/django/db/models/sql/compiler.py", line 1097, in execute_sql
cursor.execute(sql, params)
File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/django/db/backends/utils.py", line 99, in execute
return super().execute(sql, params)
File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/django/db/backends/utils.py", line 67, in execute
return self._execute_with_wrappers(sql, params, many=False, executor=self._execute)
File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/django/db/backends/utils.py", line 76, in _execute_with_wrappers
return executor(sql, params, many, context)
File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/django/db/backends/utils.py", line 84, in _execute
return self.cursor.execute(sql, params)
File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/django/db/utils.py", line 89, in __exit__
raise dj_exc_value.with_traceback(traceback) from exc_value
File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/django/db/backends/utils.py", line 84, in _execute
return self.cursor.execute(sql, params)
File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/django/db/backends/sqlite3/base.py", line 383, in execute
return Database.Cursor.execute(self, query, params)
django.db.utils.OperationalError: no such table: questioncategory

Answer 1

The problem is not your url include. The problem is that in your ErstelleFrage form you are performing a query at class level, which is executed on import; it's just that the include is the thing that is causing that form to be imported.
You should never do queries in field or form definitions like this. In this particular case, you should be using ModelChoiceField with a queryset rather than ChoiceField with an explicitly selected set of choices.