old_contents: class Train:
      drop = 'DROP TABLE IF EXISTS train'
      create = '''CREATE TABLE train(
          train_id INTEGER NOT NULL AUTO_INCREMENT,
          train_name VARCHAR(100) UNIQUE,
          PRIMARY KEY(train_id)
      ) CHARACTER SET utf8'''
  
  class Schedule:
      drop = 'DROP TABLE IF EXISTS schedule'
      create = '''CREATE TABLE schedule(
          schedule_id INTEGER NOT NULL,
          schedule_date DATE NOT NULL,
          train_id INTEGER NOT NULL,
          active INTEGER NOT NULL,
          PRIMARY KEY(schedule_id)
      ) CHARACTER SET utf8'''
  
  class Station:
      drop = 'DROP TABLE IF EXISTS station'
      create = '''CREATE TABLE station(
          station_id INTEGER NOT NULL AUTO_INCREMENT,
          station_name VARCHAR(100) UNIQUE,
          PRIMARY KEY (station_id)
      ) CHARACTER SET utf8'''
  
  class ScheduleInfo:
      drop = 'DROP TABLE IF EXISTS schedule_info'
      create = '''CREATE TABLE schedule_info(
          schedule_id INTEGER NOT NULL,
          stop_number INTEGER NOT NULL,
          station_id INTEGER NOT NULL,
          arrival_time DATETIME DEFAULT NULL,
          arrival_delay INTEGER DEFAULT NULL,
          departure_time DATETIME DEFAULT NULL,
          departure_delay INTEGER DEFAULT NULL,
          PRIMARY KEY(schedule_id, stop_number)
      ) CHARACTER SET utf8'''
  
  tables = [Train, Schedule, Station, ScheduleInfo]
  
  
new_contents: class Train:
      drop = 'DROP TABLE IF EXISTS train'
      create = '''CREATE TABLE train(
          train_id INTEGER NOT NULL AUTO_INCREMENT,
          train_name VARCHAR(100) UNIQUE,
          PRIMARY KEY(train_id)
      ) CHARACTER SET utf8'''
  
  class Schedule:
      drop = 'DROP TABLE IF EXISTS schedule'
      create = '''CREATE TABLE schedule(
          schedule_id INTEGER NOT NULL,
          schedule_date DATE NOT NULL,
          train_id INTEGER NOT NULL,
          active INTEGER NOT NULL,
          PRIMARY KEY(schedule_id)
      ) CHARACTER SET utf8'''
  
  class Station:
      drop = 'DROP TABLE IF EXISTS station'
      create = '''CREATE TABLE station(
          station_id INTEGER NOT NULL AUTO_INCREMENT,
          station_name VARCHAR(100) UNIQUE,
          PRIMARY KEY (station_id)
      ) CHARACTER SET utf8'''
  
  class ScheduleInfo:
      drop = 'DROP TABLE IF EXISTS schedule_info'
      create = '''CREATE TABLE schedule_info(
          schedule_id INTEGER NOT NULL,
          stop_number INTEGER NOT NULL,
          station_id INTEGER NOT NULL,
          arrival_time DATETIME DEFAULT NULL,
          arrival_delay INTEGER DEFAULT NULL,
          departure_time DATETIME DEFAULT NULL,
          departure_delay INTEGER DEFAULT NULL,
          PRIMARY KEY(schedule_id, stop_number)
      ) CHARACTER SET utf8'''
  
  tables = [Train, Schedule, Station, ScheduleInfo]
  
  if __name__ == "__main__":
      for table in tables:
          print(table.drop, end=';\n')
          print(table.create, end=';\n')
  
subject: print schema when ipa_db_schema.py is called