Boyce-Codd Normal Form (3.5 NF).
A database is in BCNF if following conditions met;
- It is in 3NF(1NF: no repeating groups, 2NF: Full functional dependency must exist and avoid partial dependency, 3NF: Avoid Transitive Dependency).
- For every functional dependency X->Y, X should be the super key of the table (Non-prime attribute never determines prime attribute).
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 |
Exercise 1NF to 5NF
Foreign Key behaving differently on Cascade strict and SET NullÂ
Read Tutorials about Normalization in DBMS
- First Normal form in DBMS
- Second normal form Examples in DBMS
- Third normal form
- Boyce-Codd Normal Form (3.5 NF)
- Fourth Normal Form
- Fifth Normal Form (5NF)
