Consider the Following Relational Database for Grand Travel Airlines PILOT Relation

question 95

Essay

Consider the following relational database for Grand Travel Airlines.
Grand Travel Airlines has to keep track of its flight and airplane history. A flight is uniquely identified by the combination of a flight number and a date. Every passenger who has flown on Grand Travel has a unique passenger number. For a particular passenger who has taken a particular flight, the company wants to keep track of the fare that she paid for it and the date that she made the reservation for it. Clearly, a passenger may have taken many flights (he must have taken at least one to be in the database) and every flight has had many passengers on it.
A pilot is identified by a unique pilot (or employee) number. A flight on a particular date has exactly one pilot. Each pilot has typically flown many flights but a pilot may be new to the company, is in training, and has not flown any flights, yet. Each airplane has a unique serial number. A flight on a particular date used one airplane. Each airplane has flown on many flights and dates, but a new airplane may not have been used at all, yet.
$$\begin{array} { | l | l | l | l |} \hline \text { Pilot } & \text { Pilot } & \text { Date of } & \text { Date of } \\\text { Number } & \text { Name } & \text { Birth } & \text { Hire } \\\hline\end{array}$$ PILOT Relation
$$\begin{array} { | l | l | l | l | l | l | } \hline \text { Flight } & & \text { Departure } & \text { Arrival } & \text { Pilot } & \text { Airplane } \\\text { Number } & \text { Date } & \text { Time } & \text { Time } & \text { Number } & \text { Number } \\\hline\end{array}$$ FLIGHT Relation
$$\begin{array} { | l | l | l | l | } \hline \text { Passenger } & \text { Passenger } & & \text { Telephone } \\\text { Number } & \text { Name } & \text { Address } & \text { Number }\\\hline\end{array}$$ PASSENGER Relation
$$\begin{array} { | l | l | l | l | l | } \hline \text { Flight } & & \text { Passenger } & & \text { Reservation } \\\text { Number } & \text { Date } & \text { Number } & \text { Fare } & \text { Date } \\\hline\end{array}$$ RESERVATION Relation
$$\begin{array} { | l | l | l | l | l | } \hline \text { Airplarne } & & \text { Passenger } & \text { Year } & \\\text { Number } & \text { Model } & \text { Capacity } & \text { Built } & \text { Manufacturer } \\\hline\end{array}$$ AIRPLANE Relation
Analyze each of the following situations and, using physical database design techniques, state how you would modify the logical design shown to improve performance or otherwise accommodate it.
a. There is a frequent need to quickly get detailed information about a flight and about the pilot who flew the plane.
b. It turns out that the Departure Time and Arrival Time data for flights is accessed much more frequently and requires much faster response time than the rest of the data in the FLIGHT relation.
c. The repeated use of the Flight Number and Date to access flight data is considered clumsy both in the FLIGHT relation and elsewhere where the combination is required as a foreign key.
d. When passengers phone in to get information about their flight records, the records are located by asking for the passengers' phone numbers.
e. There is a frequent (and obvious) need to be able to quickly find the number of seats that are currently taken for a flight.
f. Some people in the airline have to be able to access the pilot data but are not authorized to see the pilots' dates of birth.

Understand the role of random assignment in experiments and its impact on study outcomes.

Comprehend the significance of control groups in experimental research and how their absence can affect study conclusions.

Differentiate between experimental and correlational studies.

Understand the concepts and roles of independent and dependent variables in research.

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Definitions:

Marginal Cost

The change in total cost that arises when the quantity produced is incremented by one unit.

Retained Earnings

Profits that a company has earned to date, less any dividends or other distributions paid to shareholders, used for reinvestment in the business or to pay down debt.

After-Tax Cost

The actual cost of an investment or loan after taking into account the effects of taxation on its returns or costs.

Semi-Annual Coupon Rate

The interest rate on a bond that pays out interest twice a year.