Happy cruise lines er diagram

Happy Cruise Lines has several ships and a variety of cruise itineraries, each involving several ports-of-call. The company wants to maintain information on thesailors who currently work on each of its ships. It also wants to keep track of both its cruises and of its passengers. It wants to track passengers who took cruisesin the past and also passengers who have reservations to take cruises in the future. Each ship has at least one and, of course, normally many sailors on it. Each shiphas a unique ship number. Other ship data to track include ship name, weight, year built, and passenger capacity. Each sailor is identified by a sailor identificationnumber, as well as a name, date-of-birth, and nationality. Some of the sailors are in supervisory positions, supervising several other sailors. Each sailor reports tojust one supervisor. A cruise is identified by a unique cruise serial number. Other cruise descriptors include a departure date, a return date, and a departure port(which is also the cruise’s return point.) Clearly, a cruise involves exactly one ship; over time a ship sails on many cruises, but there is a requirement to be ableto list a new ship that has not as yet sailed on any cruises, at all. Each cruise stops at at least one and usually several ports, each of which is normally host tomany cruises, over time. In addition, the company wants to maintain information about ports that it has not as yet used in its cruises but may use in the future. Aport is identified by its name and the country that it is in. Other information about a port includes its population, whether a passport is required for the passengersto disembark there, and its current docking fee, which is assumed to be the same for all ships. Passenger information includes a unique passenger number, name, homeaddress, nationality, and date-of-birth. A cruise typically has many passengers on it (certainly at least one). Hoping for return business, the company assumes thateach passenger may have sailed on several of its cruises (and/or may be booked for a future cruise.) For a person to be of interest to the company, he or she must havesailed on or be booked on at least one of the company’s cruises. The company wants to keep track of how much money each passenger paid for (or will pay for) each oftheir cruises, as well as their satisfaction rating of the cruise, if it has been completed.