Normalization in Database (Continuation)

In Tychons, we never get fed up of sharing information and even working too. On our previous posts regarding normalization in database, we saw what is normalization? Its benefits and we saw how many different types of normalization forms are available and also we saw the first two of its types such as first and second normal form. Now let us see third normal form. 

Third Normal Form (3NF):-

(i)    Remove columns that are not fully dependent upon the primary key.

Example:-

Boys-Codd Normal Form (BCNF or 3.5NF):-

1. A relation is in Boyce-Codd Normal Form (BCNF) if every determinant is a “candidate key”.
2.  Remove the non trival functional dependency.
3.  It’s considered a special condition of third Normal form.

Candidate key:-

Define:-
 More than one primary key in the table, that primary key is called as candidate key.

3NF:-

Step:1

 Step:2

Note:-

•    For each subject, every student is educated by one teacher.
•    Every teacher teaches one subject only.
•    Each subject can be teached by more than one teacher.

3NF to BCNF:-

1)    Student is not a “Primary key”.
2)    Teacher and Subject is “Primary key”.

Note:-

A relation is in BCNF, if and only if, every determinant is a candidate key. So filter the non primary key column.

On Behalf of tychons family, i would like to thank our employee who has been sharing continuos information regarding normalization in database. Do watch our blog for regular updates on remaining types of normalization forms.