Reference no: EM133266145

Consider the following relations containing airline flight information:

Flights(flno: integer, from: string, to: string, distance: integer, departs: time, arrives: time)

Aircraft(aid: integer, aname: string, cruisingrange: integer)

Certified(eid: integer, aid: integer)

Employees(eid: integer, ename: string, salary: integer)

Note that the Employees relation describes pilots and other kinds of employees as well; every pilot is certified for some aircraft (otherwise, he or she would not qualify as a pilot), and only pilots are certified to fly.

The primary keys are underlined. The attribute names of foreign keys are not changed for easy identification. From the relational schemas illustrated above, use the different relational algebra operators and operations (ρ, σ, π, ?, ?, -, ?) discussed in class to build the following queries:

Find the eids of pilots certified for some Boeing aircraft.

Find the names of pilots certified for some Boeing aircraft.

Find the aids of all aircraft that can be used on non-stop flights from Bonn to Chicago.

Identify the flights that can be piloted by every pilot whose salary is more than $100,000.

Find the eids of employees who make the highest salary.