How to Implement Fourth Normal Form

In this article I am going to explain how to Implement fourth normal form in SQL.
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Introduction

Normalization is used to organize the content of table. Normalization is a technique which eliminate redundancy and inconsistent dependency of data from database. Normalization makes database more flexible.

Basic Goal of normalization

  • Arrange data in database in to logical grouping.
  • Eliminate redundancy of data, it means minimizing the duplicate data in database.
  • Eliminate inconsistency of data.

Fourth Normal Form

For a table in fourth normal from it must be in Boyce codd normal form (BCNF) and  it contain no multi value dependency.

Example

In this table data is in Boyce codd normal form but not in fourth normal form. 

Table in Boyce codd normal form (BCNF)  but not in Fourth Normal Form

Faculty Subject committee
Vipendra  SQL Server Placement
Vipendra Oracle Placement
Vipendra Java Placement
Vipendra  SQL Server Sport
Vipendra Oracle Sport
Vipendra Java Sport
Deepak  SQL Server Placement
Deepak Oracle Placement
Deepak Java Placement
Deepak  SQL Server Sport
Deepak Oracle Sport
Deepak Java Sport

Now we divide this table in two different tables and these tables are in fourth normal form.

Table 1  

Faculty Subject
Vipendra  SQL Server
Vipendra Oracle
Vipendra Java
Deepak  SQL Server
Deepak Oracle
Deepak Java

Table 2

Faculty committee
Vipendra Placement
Vipendra Sport
Deepak Placement
Deepak Sport

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