What is normalization and denormalization of databases? Why are they needed?

Normalization is the process of organizing data in a database to minimize redundancy and avoid anomalies during updates. It is usually achieved by dividing data into related tables using keys. Normalization improves data integrity and simplifies maintenance.

Denormalization is the reverse process, where data is deliberately duplicated or combined into a single table to enhance read performance. Denormalization reduces the number of table joins, which speeds up queries but increases the complexity of data updates.

Why they are needed:

• Normalization is necessary to maintain data cleanliness and consistency, prevent duplication and errors.
• Denormalization is applied when read speed and system load are critical, and some redundancy is acceptable.

The choice between them depends on performance requirements and data integrity.