Normalization in Database

In this article we give the information about normalization in a database design technique that organizes tables in a manner that reduce redundancy (useless) and dependency of data.

Normalization in Database:

• Normalization is a database design technique that organizes tables in a manner that reduce redundancy (useless) and dependency of data.
• To avoid insertion, update & deletion anomaly.
• Normalization divides larger tables into smaller table and link them  using relationships. (Primary key and Foreign key)

Anomaly (Insertion, Update, Delete)

Anomaly: Something that is not according to standard or normal

Table Name: student

Insert:

Insert into student (Roll_No, Name, Addrress) values (4, ‘Amol’, ‘Satara’);

Result: student does not allow null values

Update:

Update student set dept=’BCA’ where Roll_No=1;

Result: Update two rows

Delete:

Delete from student where Roll_No=1;

Result: Delete two rows

Normalization Types:

Here are most commonly used normal forms:

1. First Normal Form (1NF)
2. Second Normal Form (2NF)
3. Third Normal Form (3 NF)
4. Boyce & Codd Normal Form (BCNF)
5. Forth Normal Form (4NF)
6. Fifth Normal Form (5NF)

First Normal Form (1NF)

As per the rule of first normal form,

• An attributes (Column) of a table cannot hold multiple values.
• It should hold only atomic (forming a single unit) values.
• Each record needs to be unique.

Atomic value: An atomic value is a value that cannot be divided.

Table Name: student

Above table, column mobile number there are two mobile numbers in rows two and three so there is not an atomic value.

After First Normalization

Table Name: student

Some More: 

POP- Introduction to Programming Using ‘C’

DS – Data structure Using C

OOP – Object Oriented Programming 

Java Programming

DBMS – Database Management System

RDBMS – Relational Database Management System

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