Assignment - 1 - redoing to improve grades, Database Management System

Assignment #1
Data Management

The questions on this exam are based on the Baxter Aviation case scenario.

1. (5 points) The systems analyst proposes the following two relationships between the Flight and Pilot entities:

What question do you need to answer to decide which of the relationships is correct? (Hint:The answer requires only one sentence.)

2. A part of the initial ER diagram for the Baxter Aviation database appears as follows:

(a) (5 points) State in words the meaning of this relationship.

(b) (5 points) Why can’t this relationship be represented directly in a relational database?

(c) (5 points) Redraw the diagram so that it is compatible with the design of a relational database.

3. (10 points) Assume that you have been presented with the following relation for the Baxter Aviation database:

Charters (Pilot#, Pilot name, Aircraft ID#, #seats, Village, Flight#, Flight date, Flight time, Customer#, Customer name)

(a) How many entities are represented by this relation?

(b) What is the primary key of this relation? (Hint: Flight# is unique; flight numbers do not repeat as they do on commercial airlines with regularly scheduled flights. Each flight can go to many villages and over time a village can receive many flights.)

(c) Give a specific example of one insertion anomaly present in this relation.

(d) Give a specific example of one deletion anomaly present in this relation.

(e) Is this relation in first, second, or third normal form? Why?

4. A portion of the Baxter Aviation database is as follows:

Aircraft (Aircraft ID #, Make, Model, #seats, total airtime, hours on engine)
Village (Village name, Type of runway)
Flight (Flight time, Flight date, Aircraft ID#, Flight#, Customer #)
Destinations (Flight#, Village name)
Customers (Customer name, House number, Phone, Customer #)

(a) (5 points) Identify the primary key for each relation.

(b) (5 points) Identify all foreign keys and the primary keys they reference.

(c) (10 points) List all the constraints that must be verified whenever a row is inserted into the Flight relation. (In other words, what are the specific integrity checks that must be made?) In your list, indicate exactly which attributes are being checked and the specific test(s) being performed on each. (hint: Here’s a partial example: The database needs to validate that the primary key of the relation is unique.)

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