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First Normal Form (1NF)

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If a table has data redundancy and is not properly normalized, then it will be difficult to handle and update the database, without facing data loss. It will also eat up extra memory space and Insertion, Update, and Deletion Anomalies are very frequent if the database is not normalized. 

Normalization is the process of minimizing redundancy from a relation or set of relations. Redundancy in relation may cause insertion, deletion, and update anomalies. So, it helps to minimize the redundancy in relations. Normal forms are used to eliminate or reduce redundancy in database tables. 

Levels of Normalization

There are various levels of normalization. These are some of them: 

  • First Normal Form (1NF)
  • Second Normal Form (2NF)
  • Third Normal Form (3NF)
  • Boyce-Codd Normal Form (BCNF)
  • Fourth Normal Form (4NF)
  • Fifth Normal Form (5NF)

In this article, we will discuss the First Normal Form (1NF). 

First Normal Form with Example

If a relation contains a composite or multi-valued attribute, it violates the first normal form, or the relation is in the first normal form if it does not contain any composite or multi-valued attribute. A relation is in first normal form if every attribute in that relation is single-valued attribute. 

A table is in 1 NF if: 

  • There are only Single Valued Attributes.
  • Attribute Domain does not change.
  • There is a unique name for every Attribute/Column.
  • The order in which data is stored does not matter. 

Consider the examples given below. 

Example 1: 

Relation STUDENT in table 1 is not in 1NF because of multi-valued attribute STUD_PHONE. Its decomposition into 1NF has been shown in table 2. 



Example 2: 

ID   Name   Courses
1 A c1, c2
2 E c3
3 M c2, c3

In the above table, Course is a multi-valued attribute so it is not in 1NF. 

Below Table is in 1NF as there is no multi-valued attribute:  

ID   Name   Course
1 A c1
1 A c2
2 E c3
3 M c2
3 M c3

Note: A database design is considered as bad if it is not even in the First Normal Form (1NF).


In Conclusion, First Normal Form (1NF) is a key idea in relational database architecture. It guarantees that data is organized to facilitate data processing, remove redundancy, and support data integrity. 1NF establishes the foundation for more complex normalization strategies that further improve the correctness and efficiency of database systems by imposing atomic values and forbidding recurring groupings inside rows.

FAQs on First Normal Form

Q.1: What is the significance of 1NF in database design?


The implementation of 1NF is essential for the preservation of data integrity and productivity. It eliminates the need for redundant data and ensures that the data is structured in a manner that facilitates simple queries and operations.

Q.2: What is the first normal form (1NF)?


The first stage of database normalization, or 1NF, makes sure that there are no recurring groups inside rows and that all of a table’s columns contain atomic values, or indivisible values.

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Last Updated : 07 Nov, 2023
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