Environment:


Request Method: POST
Request URL: http://localhost:8000/courses/3/delete/

Django Version: 2.2.5
Python Version: 3.7.4
Installed Applications:
['django.contrib.admin',
 'django.contrib.auth',
 'django.contrib.contenttypes',
 'django.contrib.sessions',
 'django.contrib.messages',
 'django.contrib.staticfiles',
 'sass_processor',
 'static_pages',
 'accounts',
 'offers',
 'locations',
 'courses']
Installed Middleware:
['django.middleware.security.SecurityMiddleware',
 'django.contrib.sessions.middleware.SessionMiddleware',
 'django.middleware.common.CommonMiddleware',
 'django.middleware.csrf.CsrfViewMiddleware',
 'django.contrib.auth.middleware.AuthenticationMiddleware',
 'django.contrib.messages.middleware.MessageMiddleware',
 'django.middleware.clickjacking.XFrameOptionsMiddleware']



Traceback:

File "~/myproject/venv/lib/python3.7/site-packages/django/db/backends/utils.py" in _execute
  84.                 return self.cursor.execute(sql, params)

File "~/myproject/venv/lib/python3.7/site-packages/django/db/backends/mysql/base.py" in execute
  71.             return self.cursor.execute(query, args)

File "~/myproject/venv/lib/python3.7/site-packages/MySQLdb/cursors.py" in execute
  209.         res = self._query(query)

File "~/myproject/venv/lib/python3.7/site-packages/MySQLdb/cursors.py" in _query
  315.         db.query(q)

File "~/myproject/venv/lib/python3.7/site-packages/MySQLdb/connections.py" in query
  226.         _mysql.connection.query(self, query)

The above exception ((1451, 'Cannot delete or update a parent row: a foreign key constraint fails (`myprojectdb`.`courses_courseunit`, CONSTRAINT `courses_courseunit_course_id_b57ebb27_fk_courses_course_id` FOREIGN KEY (`course_id`) REFERENCES `courses_course` (`id`))')) was the direct cause of the following exception:

File "~/myproject/venv/lib/python3.7/site-packages/django/core/handlers/exception.py" in inner
  34.             response = get_response(request)

File "~/myproject/venv/lib/python3.7/site-packages/django/core/handlers/base.py" in _get_response
  115.                 response = self.process_exception_by_middleware(e, request)

File "~/myproject/venv/lib/python3.7/site-packages/django/core/handlers/base.py" in _get_response
  113.                 response = wrapped_callback(request, *callback_args, **callback_kwargs)

File "~/myproject/venv/lib/python3.7/site-packages/django/views/generic/base.py" in view
  71.             return self.dispatch(request, *args, **kwargs)

File "~/myproject/venv/lib/python3.7/site-packages/django/contrib/auth/mixins.py" in dispatch
  52.         return super().dispatch(request, *args, **kwargs)

File "~/myproject/venv/lib/python3.7/site-packages/django/views/generic/base.py" in dispatch
  97.         return handler(request, *args, **kwargs)

File "~/myproject/venv/lib/python3.7/site-packages/django/views/generic/edit.py" in post
  218.         return self.delete(request, *args, **kwargs)

File "~/myproject/venv/lib/python3.7/site-packages/django/views/generic/edit.py" in delete
  213.         self.object.delete()

File "~/myproject/venv/lib/python3.7/site-packages/django/db/models/base.py" in delete
  919.         return collector.delete()

File "~/myproject/venv/lib/python3.7/site-packages/django/db/models/deletion.py" in delete
  315.                 count = query.delete_batch(pk_list, self.using)

File "~/myproject/venv/lib/python3.7/site-packages/django/db/models/sql/subqueries.py" in delete_batch
  41.             num_deleted += self.do_query(self.get_meta().db_table, self.where, using=using)

File "~/myproject/venv/lib/python3.7/site-packages/django/db/models/sql/subqueries.py" in do_query
  24.         cursor = self.get_compiler(using).execute_sql(CURSOR)

File "~/myproject/venv/lib/python3.7/site-packages/django/db/models/sql/compiler.py" in execute_sql
  1100.             cursor.execute(sql, params)

File "~/myproject/venv/lib/python3.7/site-packages/django/db/backends/utils.py" in execute
  99.             return super().execute(sql, params)

File "~/myproject/venv/lib/python3.7/site-packages/django/db/backends/utils.py" in execute
  67.         return self._execute_with_wrappers(sql, params, many=False, executor=self._execute)

File "~/myproject/venv/lib/python3.7/site-packages/django/db/backends/utils.py" in _execute_with_wrappers
  76.         return executor(sql, params, many, context)

File "~/myproject/venv/lib/python3.7/site-packages/django/db/backends/utils.py" in _execute
  84.                 return self.cursor.execute(sql, params)

File "~/myproject/venv/lib/python3.7/site-packages/django/db/utils.py" in __exit__
  89.                 raise dj_exc_value.with_traceback(traceback) from exc_value

File "~/myproject/venv/lib/python3.7/site-packages/django/db/backends/utils.py" in _execute
  84.                 return self.cursor.execute(sql, params)

File "~/myproject/venv/lib/python3.7/site-packages/django/db/backends/mysql/base.py" in execute
  71.             return self.cursor.execute(query, args)

File "~/myproject/venv/lib/python3.7/site-packages/MySQLdb/cursors.py" in execute
  209.         res = self._query(query)

File "~/myproject/venv/lib/python3.7/site-packages/MySQLdb/cursors.py" in _query
  315.         db.query(q)

File "~/myproject/venv/lib/python3.7/site-packages/MySQLdb/connections.py" in query
  226.         _mysql.connection.query(self, query)

Exception Type: IntegrityError at /courses/3/delete/
Exception Value: (1451, 'Cannot delete or update a parent row: a foreign key constraint fails (`myprojectdb`.`courses_courseunit`, CONSTRAINT `courses_courseunit_course_id_b57ebb27_fk_courses_course_id` FOREIGN KEY (`course_id`) REFERENCES `courses_course` (`id`))')