Chapter 2, Problem 2.19RQ

Explanation of Solution

According to the reference of book, the terms “primary key” and “foreign key” are defined as follows:

Primary key:

• Primary key is like a candidate key in which it uniquely identifies each row in a relation.
  • For example consider that there is an “Employee” table in which “emp_id” is unique so it is chosen as a primary key in database table.
  • In this book, primary keys are underlined.

Foreign key:

• To maintain the relationship between the database tables, the values are placed from one relation to second relation.
• The values used in first relation come under the primary key values whereas the values that are referred in second relation come under the foreign key...