What is denormalization and what is it used for?

Denormalization is the process of intentionally adding redundancy to a database, that is, duplicating data to speed up read operations and simplify queries.

In normalized databases, data is divided into multiple related tables, which reduces redundancy and prevents update anomalies. However, this can slow down read operations due to the need to perform complex JOIN queries.

Denormalization is used when high read performance is important and some redundancy is acceptable. For example, in systems with a high volume of read requests where response speed is critical.

Example: instead of storing the user's name only in the users table and referencing it via ID, you can add the user's name directly into the orders table to quickly display information without a JOIN.