Question

A relation is in third normal form if it is in second normal form and there are no functional dependencies between two (or more) non-primary key attributes.

Answer 1

The third normal form (3NF) in database design aims to reduce redundancy and improve data integrity by eliminating transitive dependencies. It is a level of normalization that builds upon the second normal form (2NF).

Step-by-step explanation:

In database design, the concept of normalization is used to reduce redundancy and improve data integrity. The third normal form (3NF) is a level of normalization that builds upon the second normal form (2NF) and introduces the concept of eliminating transitive dependencies. A relation is said to be in 3NF if it satisfies the conditions of 2NF and there are no functional dependencies between non-primary key attributes.

Let's take an example to illustrate this. Suppose we have a relation called 'Student' with attributes like Student_ID, Student_Name, Student_Address, and Course_ID. Here, Student_ID is the primary key, and there is a functional dependency between Student_ID and Student_Name, as well as between Course_ID and Student_Address. However, there is no functional dependency between Student_Name and Student_Address. To bring this relation to 3NF, we can decompose it into two relations: 'Student_Info' (containing Student_ID, Student_Name, and Student_Address) and 'Course_Info' (containing Student_ID and Course_ID).