namespace airline;

class Airline{
  singleton;
  1 -- * RegularFlight;
  1 -- * Person;
}

class RegularFlight{
  Time time;
  Integer flightNumber;
  1 -- * SpecificFlight;
  key{flightNumber}
}

class SpecificFlight{
  Integer flightId;
  Date date;
  key{flightId}
}

class PassengerRole
{
  isA PersonRole;
  immutable String name ;
  1 -- * Booking;
  key{name}
}
  

class EmployeeRole
{
  String jobFunction;
  isA PersonRole;
  * -- 0..1 EmployeeRole supervisor;
  * -- * SpecificFlight;
  key{jobFunction}
}

class Person
{
  String name;
  Integer idNumber;
  1 -- 0..2 PersonRole;
  key{idNumber}
}

class PersonRole{}

class Booking{
  Integer sequenceNumber;
  String seatNumber;
  * Booking -- 1 SpecificFlight;
  key{sequenceNumber}
}