Other Normal Forms
Boyce-Codd Normal Form (BCNF)
Sometimes, when the database is in the 3rd Normal Form, there exist some anomalies in DBMS, like when more than one Candidate Keys is present in the Database. This has to be removed under BCNF. BCNF is also called 3.5NF.
4th Normal Form
Whenever a Database contains multivalued and independent data in two or more tables, then the database is to be considered in the 4th Normal Form.
5th Normal Form
Whenever a Database Table is not in 4NF, and we cannot divide it into smaller tables keeping our data safe with us, then our Database is in 5th Normal Form.
Normalization Process in DBMS
Pre-Requisite: Introduction to Database Normalization
Database Normalization is a stepwise formal process that allows us to decompose database tables in such a way that both data dependency and update anomalies are minimized. It makes use of functional dependency that exists in the table and the primary key or candidate key in analyzing the tables. Normal forms were initially proposed called
Subsequently, R, Boyce, and E. F. Codd introduced a stronger definition of 3NF called Boyce-Codd Normal Form. With the exception of 1NF, all these normal forms are based on functional dependency among the attributes of a table. Higher normal forms that go beyond BCNF were introduced later such as Fourth Normal Form (4NF) and Fifth Normal Form (5NF). However, these later normal forms deal with situations that are very rare.
Normalization Process in DBMS
Now, we are going to describe the process of Normalization by considering an Example. Let us look into that.