What is De-normalization?

In computing, de-normalization is the process of attempting to optimize the read performance of a database by adding redundant data or by grouping data. In some cases, de-normalization is a means of addressing performance or scalability in relational database software. De-normalization is the process of attempting to optimize the performance of a database by adding redundant data. It is sometimes necessary because current DBMSs implement the relational model poorly. A true relational DBMS would allow for a fully normalized database at the logical level, while providing physical storage of data that is tuned for high performance. De-normalization is a technique to move from higher to lower normal forms of database modeling in order to speed up database access.