Exercise 6Create 2 tables, LAB7_RESERVATIONS table with 2 columns:Name Null Type---------- ------------- ---------------FLIGHT_ID NOT NULL CHAR(6)CUSTOMER_PHONE NOT NULL NUMBERand LAB7_FLIGHTS table with 2 columns:FLIGHT_ID NOT NULL CHAR(6)SEATS NOT NULL NUMBERMake FLIGHT_ID the primary key in the LAB7_FLIGHTS table.Insert the following rows into LAB7_FLIGHTS: COSC 304 – Lab 7 (Triggers) Page 7FLIGHT_ID SEATSAC0529 120AC0530 0Create a trigger LAB7_RES_TRG that will ensure that when a new row is inserted into theLAB7_RESERVATIONS table, the flight id is in the LAB7_FLIGHTS table and that the numberof seats on this flight, SEATS is greater than 0. Here are the details of how the trigger shouldbehave:
If flight id is not in the flights table it should raise application error ‘Invalid flight id’
If flight id is in the flights table, (for example AC0529) but SEATS = 0, then it should raiseapplication error ‘Flight AC0529 has no seats left’
If flight id is in the flights table and SEATS > 0, then it should update the appropriate row inflights table by setting SEATS = SEATS – 1 for this flight.(Hint: Use the PL/SQL statement select .. into .. )