Database Normalisation Questions Medium
The fifth normal form (5NF), also known as Project-Join Normal Form (PJNF), is a level of database normalization that aims to eliminate redundancy and dependency among multiple join dependencies. It is used in situations where a database schema has multiple join dependencies and requires further normalization beyond the third normal form (3NF) and fourth normal form (4NF).
5NF is primarily used in complex database systems where there are multiple overlapping join dependencies. It helps to ensure that the database schema is free from redundancy and anomalies, allowing for efficient data storage, retrieval, and modification.
To achieve 5NF, the database schema is decomposed into smaller tables based on the join dependencies. Each table represents a single join dependency, and the relationships between these tables are maintained through foreign key constraints. This decomposition eliminates redundancy and ensures that each table contains only non-redundant and non-overlapping data.
By using 5NF, database designers can optimize the performance of complex database systems, improve data integrity, and simplify data management. However, it is important to note that achieving 5NF may result in increased complexity and may require more advanced database design and query optimization techniques.