Question

What is the method of specifying a primary key in a schema description?

(a) By writing it in bold letters

(b) By underlining it using a dashed line

(c) By writing it in capital letters

(d) By underlining it using a bold line

The question was posed to me at a job interview.

This intriguing question comes from Introduction to the Relational Model in chapter Introduction to Relational Model and Sql of RDBMS

Answer 1

The correct option is (d) By underlining it using a bold line

The best explanation: We can specify a primary key in schema description by underlining the respective attribute with a bold line.