Chapter 2

Question 1

T||F : Every table is a relation, but not very relation is a table.

Answer 1

False

Question 2

T||F : Every cell in a relation can hold only a single value.

Answer 2

True

Question 3

T||F : To be considered a composite key, a key must contain at least two attributes.

Answer 3

True

Question 4

T||F : When used to represent a relationship, the primary key must have the same name as the corresponding foreign key.

Answer 4

False

Question 5

If the condition exists such that knowing the value of attribute X determines the value of attribute Y, then attribute Y is functionally dependent on attribute X.

Answer 5

True

Question 6

What is synonymous with “tuple”?

Answer 6

Row

Question 7

Keys

Answer 7

It may be unique
It may be non-unique
In may identify more than one row

Question 8

STUDENT (SID, StudentName, Major, AdvisorID)

ADVISOR (AdvisorID, AdvisorName, Office, Phone)

Answer 8

AdvisorID is a foreign key

Question 9

Null Values Falseness

Answer 9

A null value can mean that no value for the field is appropriate

Question 10

Briefly describe the various tasks of the primary key

Answer 10

While a primary key helps identify unique columns, they also help create indexes for databases and help ensure that no value is repeated

Question 11

Concept of a foreign key

Answer 11

Foreign key are primary keys in another table

Question 12

Concept of functional dependency

Answer 12

Functional dependency is when a value of a table dependency on another value. This validates the data.