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6.17. Consider the AIRLINE relational database schemashown in Figure 5.8, which was described in Exercise 5.12.Specify the following queries in relational algebra: a. For each flight, list the flight number, the departureairport for the first leg of the flight, and the arrival airportfor the last leg of the flight. دحألولحلاDEPARTURE = Flight_numberξMIN Leg_number (FLIGHT_LEG) Departure_airport = πFlight_number,Departure_airport_code(DEPARTURE *FLIGHT_LEG )ARRIVAL = Flight_numberξMAX Leg_number (FLIGHT_LEG) Arrival _airport = πFlight_number, Arrival_airport_code(ARRIVAL *FLIGHT_LEG )RESUL<- Departure_airport * Arrival _airportلحرخأDEPARTURE = Flight_numberξMIN Leg_number (FLIGHT_LEG) ARRIVAL = Flight_numberξMAX Leg_number (FLIGHT_LEG) RESUL<-πFlight_number,Departure_airport_code,Arrival_airport_code((DEPARTURE×ARRIVAL)*AIRPORT)b.List the flight numbers and weekdays of all flights orflight legs that depart from Houston Intercontinental Airport