First Normal Form (1NF)

Gaurish Anand
Last Updated: May 13, 2022

Introduction

Before beginning, let's recap what does normalization means. 

Normalization is used to remove the redundancy and inconsistent dependence in the database. Anomalies in insertion, deletion, and update can be caused by relation redundancy. 

To normalize a dataset, we break down this large dataset into different smaller datasets depending upon the relationships among tables. 
 

You can go through this article to learn more about normalization.

There are various types of normal forms. Some of them are 

  1. First Normal Form (1NF)
  2. Second Normal Form (2NF)
  3. Third Normal Form (3NF)
  4. Boyce Codd Normal Form (BCNF


Here, we will be discussing the first normal form.

First Normal Form

According to the first normal form, a table can’t have multi-valued attributes, so all the attributes should be single-valued. 

For a table to be in 1NF, it should follow these rules: 

  1. The table does not contain composite or multi-valued attributes.
  2. Every Attribute/Column should have a different name.
  3. There should be no difference in which order data is stored.
  4. The domain of the attribute should not change.


Example: 

Because of the multi-valued attribute STUD_PHONE, the relation STUDENT is not in 1NF

STUDENT table: 

The above table decomposed into 1NF will like this: 

Frequently Asked Questions

  1. What is RDBMS?
    A relational database management system is software that stores, manages, queries, and retrieves data from a relational database (RDBMS).
     
  2. What is SQL?
    Structured Query Language (SQL) is used for storing and managing data in a relational database management system (RDBMS).
     
  3. Why are normalization and denormalization used in databases?
    Normalization is used in databases to reduce redundancy and improve overall data integrity. Denormalization is a technique performed after the normalization of databases to enhance the efficiency of select queries involving several join operations.

Key Takeaways

We learned about the first normal form(1NF) in this article.

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