Denormalization in Databases

Denormalization is a strategy used on a previously-normalized database to increase performance. In computing, denormalization is the process of trying to improve the read performance of a database, at the expense of losing some write performance, by adding redundant copies of data or by grouping data.

What is the advantage of denormalization?

Denormalization can improve performance by: Minimizing the need for joins. Precomputing aggregate values, that is, computing them at data modification time, rather than at select time. Reducing the number of tables, in some cases.