Use the database shown in Figures 4&5 to answer Problems 1316. ROBCOR is an aircraft charter company that supplies on-demand charter flight services using a fleet of four aircraft. Aircrafts are identified by a unique registration number. Therefore, the aircraft registration number is an appropriate primary key for the AIRCRAFT table. Database name: Ch03 AviaCo The destinations are indicated by standard three-letter airport codes. For example, STL - St. Louis, MO ATL= Atlanta, GA BNA - Nashville, TM Table name: AIRCRAFT \( \begin{array}{ll}\text { AC_TTAF } & \text { - Aircraft total time, airframe (hours) } \\ \text { AC_TTEL } & \text { - Total time, left engine (hours) } \\ \text { AC_TTER } & \text { - Total time, right engine (hours) }\end{array} \) In a fully developed database system, such attribute values would be updated by application software when the CHARTER table entries are posted. Table nama: MnnFI Customers are charged per roundtrip mile, using the MOD_CHG_MLE rate. The MOD_SEATS gives the total number of seats in the airplane, including the pilot and copilot seats. Therefore, a PA31.350 trip that is flown by a pilot and a copilot has eight passenger seats available. Database name: Ch03_AviaCo The pilot licenses shown in the PILOT table include the ATP - Alrline Transport Pilot and COM = Commercial Plot. Businesses that operate "on demand" elr services are govemed by Part 135 of the Federal Alr. Regulations (FARs) that are enforced by the Federal Aviation Administration (FAA). Such busineses are known as "Part 135 operators." Part 135 operations require that pilots successfully complete flight proficlency checks each six months. The "Part 135 " flight proficiency check date is recorded in PIL. PT135 DATE. To Nly commercially, pilots must have at least a commercial license and a 2 and class medical certificate (PIL_MED_TYPE - 2.) The nulls in the CHARTER table 's CHAR COPILOT column indicate that a copilot is not required for some charter trips or for some aircraft. Federal Aviation Administration (FAA) rules require a copilot on jet aircraft and on aircraft having a gross take-off weight over 12,500 pounds. None of the aircraft in the AIRCRAFT table are governed by this requirement; however, some customers may require the presence of a copilot for insurance reasons. All charter trips are recorded in the CHARTER table. 13. For each table, identify the primary key and foreign key(s) when possible. You want to see data on charters flown by either Robert WHiliams (employee number105) or Elizabeth Travis (employee number 109) as pilot or copilot, but not charters flown by both of them. Complete Problems 14-16 to find this information. 14. Create the table that would result from applying the SELECT and PROJECT relational operators to the CHARTER table to return only the CHAR_TRIP, CHAR_PILOT, and CHAR COPILOT attributes for charters flown by either employee 105 or employee 109 as pilot or copilot. 15. Create the table that would result from applying the SELECT and PROJECT relational operators to the CHARTER table to return only the CHAR_TRIP, CHAR_PILOT, and CHAR COPILOT attributes for charters flown by both employee 105 and employee 109. 16. Create the table that would result from applying a DIFFERENCE relational operator of your result from Problem 14 to your result from Problem 15