basic concept of normalization - Wikitechy

Normal Forms in DBMS ?

webmaster — Wed, 26 Oct 2022 09:22:43 +0000

There are 4 types of form in Normalization :

First Normal Form(1NF)

If a relation does not contain any multi valued attributes, then the relation is said to be in First Normal Form.
A relation is said to be in First Normal Form if each attributes contains only single value.
Rule of First normal form states that an attribute of a table cannot have multiple values. It can have only single values.

Second Normal Form(2NF)

A table is said to be second normal form on two conditions
Table should be in First Normal Form(1NF).
Any non-prime attribute is not dependent on the proper subset of the candidate key of the table.
Non prime attribute is an attribute which is not a part of any candidate key.

Third Normal Form(3NF)

A design of the table is said to be third normal form(3NF) only if
A Table is in second normal form(2NF)
Transitive functional dependency of non-prime attribute on any super key should be removed.
Non prime attribute is an attribute which is not a part of any candidate key.

Boycee & Codd Normal Form(BCNF)

An advanced version of third normal form is known as Boycee & Codd Normal Forms(BCNF).
BCNF is stricter than third normal form.
A table is said to be in BCNF if it is already in 3NF and every functional dependency should be the super key of the table.