old_contents: """
  Custom fields for use in the coursewarehistoryextended django app.
  """
  
  from django.db.models.fields import AutoField
  
  
  class UnsignedBigIntAutoField(AutoField):
      """
      An unsigned 8-byte integer for auto-incrementing primary keys.
      """
      def db_type(self, connection):
          if connection.settings_dict['ENGINE'] == 'django.db.backends.mysql':
              return "bigint UNSIGNED AUTO_INCREMENT"
          elif connection.settings_dict['ENGINE'] == 'django.db.backends.sqlite3':
              # Sqlite will only auto-increment the ROWID column. Any INTEGER PRIMARY KEY column
              # is an alias for that (https://www.sqlite.org/autoinc.html). An unsigned integer
              # isn't an alias for ROWID, so we have to give up on the unsigned part.
              return "integer"
          elif connection.settings_dict['ENGINE'] == 'django.db.backends.postgresql_psycopg2':
              # Pg's bigserial is implicitly unsigned (doesn't allow negative numbers) and
              # goes 1-9.2x10^18
              return "BIGSERIAL"
          else:
              return None
  
new_contents: """
  Custom fields for use in the coursewarehistoryextended django app.
  """
  
  from django.db.models.fields import AutoField
  
  
  class UnsignedBigIntAutoField(AutoField):
      """
      An unsigned 8-byte integer for auto-incrementing primary keys.
      """
      def db_type(self, connection):
          if connection.settings_dict['ENGINE'] == 'django.db.backends.mysql':
              return "bigint UNSIGNED AUTO_INCREMENT"
          elif connection.settings_dict['ENGINE'] == 'django.db.backends.sqlite3':
              # Sqlite will only auto-increment the ROWID column. Any INTEGER PRIMARY KEY column
              # is an alias for that (https://www.sqlite.org/autoinc.html). An unsigned integer
              # isn't an alias for ROWID, so we have to give up on the unsigned part.
              return "integer"
          elif connection.settings_dict['ENGINE'] == 'django.db.backends.postgresql_psycopg2':
              # Pg's bigserial is implicitly unsigned (doesn't allow negative numbers) and
              # goes 1-9.2x10^18
              return "BIGSERIAL"
          else:
              return None
  
      def rel_db_type(self, connection):
          if connection.settings_dict['ENGINE'] == 'django.db.backends.mysql':
              return "bigint UNSIGNED"
          elif connection.settings_dict['ENGINE'] == 'django.db.backends.sqlite3':
              return "integer"
          elif connection.settings_dict['ENGINE'] == 'django.db.backends.postgresql_psycopg2':
              return "BIGSERIAL"
          else:
              return None
  
subject: Add a rel_db_type to UnsignedBigIntAutoField