6.1. One of the migrations fails

6.1.1. Problem

During migrations, an error message similar to the one below is printed:

Traceback (most recent call last):
  File "manage.py", line 10, in <module>
    execute_from_command_line(sys.argv)
  File "/usr/local/lib/python3.5/site-packages/django/core/management/__init__.py", line 367, in execute_from_command_line
    utility.execute()
  File "/usr/local/lib/python3.5/site-packages/django/core/management/__init__.py", line 359, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/usr/local/lib/python3.5/site-packages/django/core/management/base.py", line 294, in run_from_argv
    self.execute(*args, **cmd_options)
  File "/usr/local/lib/python3.5/site-packages/django/core/management/base.py", line 345, in execute
    output = self.handle(*args, **options)
  File "/usr/local/lib/python3.5/site-packages/django/core/management/commands/migrate.py", line 204, in handle
    fake_initial=fake_initial,
  File "/usr/local/lib/python3.5/site-packages/django/db/migrations/executor.py", line 115, in migrate
    state = self._migrate_all_forwards(state, plan, full_plan, fake=fake, fake_initial=fake_initial)
  File "/usr/local/lib/python3.5/site-packages/django/db/migrations/executor.py", line 145, in _migrate_all_forwards
    state = self.apply_migration(state, migration, fake=fake, fake_initial=fake_initial)
  File "/usr/local/lib/python3.5/site-packages/django/db/migrations/executor.py", line 244, in apply_migration
    state = migration.apply(state, schema_editor)
  File "/usr/local/lib/python3.5/site-packages/django/db/migrations/migration.py", line 129, in apply
    operation.database_forwards(self.app_label, schema_editor, old_state, project_state)
  File "/usr/local/lib/python3.5/site-packages/django/db/migrations/operations/models.py", line 96, in database_forwards
    schema_editor.create_model(model)
  File "/usr/local/lib/python3.5/site-packages/django/db/backends/base/schema.py", line 295, in create_model
    self.execute(sql, params or None)
  File "/usr/local/lib/python3.5/site-packages/django/db/backends/base/schema.py", line 112, in execute
    cursor.execute(sql, params)
  File "/usr/local/lib/python3.5/site-packages/django/db/backends/utils.py", line 79, in execute
    return super(CursorDebugWrapper, self).execute(sql, params)
  File "/usr/local/lib/python3.5/site-packages/django/db/backends/utils.py", line 64, in execute
    return self.cursor.execute(sql, params)
  File "/usr/local/lib/python3.5/site-packages/django/db/utils.py", line 94, in __exit__
    six.reraise(dj_exc_type, dj_exc_value, traceback)
  File "/usr/local/lib/python3.5/site-packages/django/utils/six.py", line 685, in reraise
    raise value.with_traceback(tb)
  File "/usr/local/lib/python3.5/site-packages/django/db/backends/utils.py", line 62, in execute
    return self.cursor.execute(sql)
  File "/usr/local/lib/python3.5/site-packages/django/db/backends/mysql/base.py", line 110, in execute
    return self.cursor.execute(query, args)
  File "/usr/local/lib/python3.5/site-packages/MySQLdb/cursors.py", line 226, in execute
    self.errorhandler(self, exc, value)
  File "/usr/local/lib/python3.5/site-packages/MySQLdb/connections.py", line 36, in defaulterrorhandler
    raise errorvalue
  File "/usr/local/lib/python3.5/site-packages/MySQLdb/cursors.py", line 217, in execute
    res = self._query(query)
  File "/usr/local/lib/python3.5/site-packages/MySQLdb/cursors.py", line 378, in _query
    rowcount = self._do_query(q)
  File "/usr/local/lib/python3.5/site-packages/MySQLdb/cursors.py", line 341, in _do_query
    db.query(q)
  File "/usr/local/lib/python3.5/site-packages/MySQLdb/connections.py", line 280, in query
    _mysql.connection.query(self, query)
django.db.utils.OperationalError: (1050, "Table 'courses_coursesuccession' already exists")

6.1.2. Solution

• Shut down all containers: docker-compose down
• Delete all docker containers and volumes. Delete the containers first in order to be able to delete the associated volumes. WARNING: This erases the entire database on your system. Useful commands: - docker container ls to get the ID of the containers, docker container rm [ID] to remove the container whose ID is [ID] - docker volume ls to get the ID of the volumes, docker volume rm [ID] to remove the volume whose ID is [ID]
• Start the server: docker-compose up
• In another terminal (while the server is still running): mysql -h 127.0.0.1 --port=3309 -u root -proot -t tq_website < path/to/dump_now.sql, where you have to set the correct path to the database dump that your IT board member gave you. Wait until this command has completed.
• Kill the server.
• Run scripts/migrate.sh from within the folder where the TQ website code is located.
• Start the server using docker-compose up. Your server should work fine now.