Question 4: Figure 3 shows an ER diagram for a database that may be used to keep track of an AIRLINE. Map this schema into a relational schema, and specify all primary keys and foreign keys. Airport code City State Name DEPARTURE AIRPORT 1 N Lee.no AIRPORT Scheduled_dep_time Scheduled arr time FLIGHT LEG N N M CAN ARRIVAL AIRPORT Instances LEGS LAND Number FLIGHT 1 ( Typenam Marse INSTANCE OF Company Airline AIRPLANE N Arr_time TYPE Wookday DEPARTS N ARRIVES Restrictions Dop time TYPE N Amount IN Scode FARES N FARE Airplane Total no of seats No of avail este AIRPLANE N ASSIGNED LEG INSTANCE Rate Customer name Cphone Soatno RESERVATION SEAT Figure 3: An ER diagram for an AIRLINE database schema