Which of the following should be a primary key?
a) person’s last name
b) employee’s salary
c) customer id number
d) salesperson’s rigor
Which filed listed below is the most appropriate primary key?
a) person’s name
b) person’s street address
c) person’s birth date
d) person’s social security number
How many types of keys in relational database?
a) four
b) five
c) six
d) seven
Explanation: super key, candidate key, primary key, alternate key, composite key, foreign key
One field or combination of fields for which more than one record may have the same combination of values is called
a) secondary key
b) index
c) composite key
d) linked key
Which of the following is a candidate key?
a) primary key selected to key of relation
b) an attribute or group of attributes
c) primary key
d) all of these
An attribute in a relation of a database that serves as the primary key of another relation in the same database is called…
a) global key
b) link key
c) foreign key
d) none of these
