Boyce-Codd Normal Form (3.5 NF)

By: Prof. Fazal Rehman Shamil
Last modified on January 31st, 2021

Boyce-Codd Normal Form (3.5 NF).

A database is in BCNF if following conditions met;

  1. It is in 3NF(1NF: no repeating groups, 2NF: Full functional dependency must exist and avoid partial dependency, 3NF: Avoid Transitive Dependency).
  2. For every functional dependency X->Y, X should be the super key of the table (Non-prime attribute never determines prime attribute).

3.5 NF Boyce Codd Normal Form (BCNF) Diagram

Example
For example, we have a table, with some data. The given table is not in BCNF.

Author Nationality Book title Category Number of pages
Author_A Pakistani Data Mining Concepts by T4Tutorials Comedy 700
Author_B Indian Database Systems by T4Tutorials Textbook 350
Author_C American Software Engineering Concepts by T4Tutorials Textbook 300
Author_D American Software Engineering Concepts by T4Tutorials Textbook 300

 

Author Nationality
Author_A Pakistani
Author_B Indian
Author_C American
Author_D American
Book title Category Number of pages
Data Mining Concepts by T4Tutorials Comedy 700
Database Systems by T4Tutorials Textbook 350
Software Engineering Concepts by T4Tutorials Textbook 300

 

Author Book title
Author_A Data Mining Concepts by T4Tutorials
Author_B Database Systems by T4Tutorials
Author_C Software Engineering Concepts by T4Tutorials
Author_D Software Engineering Concepts by T4Tutorials

Video Lecture

Excercise 1NF to 5NF

 

Prof. Fazal Rehman Shamil