Software Architect's Handbook

Denormalizing a database

For performance and scalability reasons, there may be cases where it makes sense to denormalize part of the database. It is important to differentiate between a database that has not been normalized, and one that has been normalized and then is denormalized later. A database should be normalized first and then if there are cases where it makes sense to denormalize, it should be done after careful consideration.

Denormalization is a strategy used to improve performance, typically by shortening the execution time of certain queries. This can be accomplished by storing redundant copies of some data or grouping data together in order to minimize joins and improve query performance.

While denormalization might improve ...