Define the primary key used for each entity in Problem 11.

Problem 11

A bus operator transfers data every day from a handheld ticket machine to his agency’s server at the end of his workday. The data contains trip details: journeys for the day, the number of tickets issued, total fare collected, passes availed, and so on. At the end of the day, the shift manager enters the trip number, the operator number, and the date in the server’s trip management system to generate a report of totals for verification. Draw an E-R diagram for this situation considering only three entities: trips, operator, and fare.