Chapter 4 – ‘Relational Databases’

Question 1

1. The relational data model portrays data as being stored in __________.

a. hierarchies
b. tables
c. objects
d. files

Answer 1

b. tables (Correct. The relational data model portrays data as being stored in a table or relation format.)

Question 2

2. How a user conceptually organizes and understands data is referred to as the __________.

a. physical view
b. logical view
c. data model view
d. data organization view

Answer 2

b. logical view (Correct. The logical view shows how a user conceptually organizes and understands data.)

Question 3

3. What is each row in a relational database table called?

a. relation
b. attribute
c. anomaly
d. tuple

Answer 3

d. tuple (Correct. A tuple is also called a row in a relational database.)

Question 4

4. Which of the following is an individual user’s view of the database?

a. conceptual-level schema
b. external-level schema
c. internal-level schema
d. logical-level schema

Answer 4

b. external-level schema (Correct. The external-level schema represents an individual user’s view of the database.)

Question 5

5. Which of the following would managers most likely use to retrieve information about sales during the month of October?

a. DML
b. DSL
c. DDL
d. DQL

Answer 5

d. DQL (Correct. DQL—data query language—is used to retrieve information from a database.)

Question 6

6. Which of the following attributes would most likely be a primary key?

a. supplier name
b. supplier number
c. supplier Zip code
d. supplier account balance

Answer 6

b. supplier number (Correct. A unique number can be assigned as a primary key for each entity.)

Question 7

7. Which of the following is a software program that runs a database system?

a. DQL
b. DBMS
c. DML
d. DDL

Answer 7

b. DBMS (Correct. A DBMS—database management system—is a software program)

Question 8

8. The constraint that all primary keys must have nonnull data values is referred to as which of the following?

a. referential integrity rule
b. entity integrity rule
c. normalization rule
d. relational data model rule

Answer 8

b. entity integrity rule (Correct. Every primary key in a relational table must have a nonnull value.)

Question 9

9. The constraint that all foreign keys must have either null values or the value of a primary key in another table is referred to as which of the following?

a. referential integrity rule
b. entity integrity rule
c. foreign key value rule
d. null value rule

Answer 9

a. referential integrity rule (Correct. The referential integrity rule stipulates that foreign keys must have values that correspond to the value of a primary key in another table or be empty.)

Question 10

10. Which of the following attributes in the Cash Receipts table (representing payments received from customers) would most likely be a foreign key?

a. cash receipt number
b. customer check number
c. customer number
d. cash receipt date

Answer 10

c. customer number (Correct. Customer number would be a foreign key in the Cash Receipts table and would link the Cash Receipts table to the Customer Table.)