Question

Scenic Routes operates a bus company that specializes in traveling on secondary roads, rather than Interstate highways. Their slogan is: “It Takes a Little Longer, But It’s Scenic.” The firm needs to update its passenger reservation system.

Background

Data items must include reservation number, Route Number, Date, Origin, Destinations, Departure Time, Arrival Time, Passenger Name, and Seat Number. For example, Route 97 leaves Monroe, VA, daily at 8:00 a.m. and arrives in Spencer, VA, 100 miles away, at 11:00 a.m. Scenic wants to use an alphabetic reservation code, similar to the codes that airlines use.

Tasks

1. Identify the entities and their relationships. Then create an ERD for the reservations system.
2. Create 3NF table designs for the system.
3. For each of the entities identified, design tables and identify the possible candidate keys, the primary key, a probable foreign key, and potential secondary keys.
4. Use sample data to populate the fields for three records.

Answer 1

Identify the entities and their relationships. Then create an ERD for the reservations system.

A sample ERD follows. Note that the RESERVATION CODE DATA entity might store data about the Reservation Code, Date, Route Number, Passenger Name, and Seat Number. The ROUTE DATA entity might store data about the Route Number, Origin, Destination, Departure Time, and Arrival Time.

Create 3NF table designs for the system.

ROUTE DATA (ROUTE NUMBER, ORIGIN, DESTINATION, DEPART TIME, ARRIVE TIME)

RESERVATION DATA (RESERVATION CODE, DATE, ROUTE NUMBER, FLIGHT NUMBER, LIGHT DATE, PASSENGER NAME, and SEAT NUMBER)

PASSENGER NAME (PASSENGER NUMBER, PASSENGER LAST NAME, PASSENGER FIRST NAME)

For each of the entities identified, design tables and identify the possible candidate keys, the primary key, a probable foreign key, and potential secondary keys. Use sample data to populate the fields for three records.

ROUTE DATA (ROUTE NUMBER, ORIGIN, DESTINATION, DEPART TIME, ARRIVE TIME)

• Candidate keys: Route Number is the only candidate key. No other field will identify flights uniquely.
• Primary key: Route Number is the primary key.
• Foreign key: This record requires no foreign key.
• Secondary keys: Potential secondary keys include ORIGIN, DESTINATION, DEPART TIME, and ARRIVE TIME. Scenic Routes might want to access or display data on the basis of any of these fields, or a combination of them. Using this design, sample data for three ROUTE DATA records might look like this:

ROUTE NUMBER	ORIGIN	DESTINATION	DEPART TIME	ARRIVE TIME	FREQUENCY
368	AUG	NAS	0923	1017	TTH
890	HPN	AUG	1410	1555	DLY
900	AUG	AUG	1535	1620	TTH

RESERVATION DATA (RESERVATION CODE, DATE, ROUTE NUMBER, FLIGHT NUMBER, FLIGHT DATE, PASSENGER NAME, and SEAT NUMBER)

• Primary and Candidate keys: RESERVATION CODE is a unique value assigned as a primary key. A candidate key might be constructed as a combination of ROUTE NUMBER, DATE, and PASSENGER NUMBER, but there would be no real advantage..
• Foreign key: PASSENGER NUMBER and ROUTE NUMBER are foreign keys.
• Secondary keys: DATE, PASSENGER NUMBER, ROUTE NUMBER, and SEAT NUMBER also can be used as secondary keys.

Using this design, sample data for three RESERVATION DATA records might look like this:

RESERVATION CODE	DATE	ROUTE NUMBER	PASSENGER NUMBER	SEAT NUMBER
AXQTBC	7/6/14	368	ALER1098	2A
SUVZAB	6/1/14	890	BROT4657	11A
RHJBVS	6/1/14	890	BROT6182	11B

PASSENGER NAME (PASSENGER NUMBER, PASSENGER LAST NAME, PASSENGER FIRST NAME)

• Candidate keys: There are no candidate keys other than PASSENGER NUMBER.
• Primary key: PASSENGER NUMBER is the primary key.
• Foreign key: This record requires no foreign key.
• Secondary keys: PASSENGER NAME is a secondary key.
• Using this design, sample data for three PASSENGER records might look like this:

PASSENGER NUMBER	PASSENGER LAST NAME	PASSENGER FIRST NAME
ALER1098	Alerion	Nathan
BROT4657	Brothers	Barbara
BROT6182	Brothers	Sam