What is De-normalization?
De-normalization is the method of attempting to optimize the performance of a database by adding redundant data. It is sometimes essential because current DBMSs execute the relational model poorly. A true relational DBMS would allow for a fully normalized database at the logical level, whereas providing physical storage of data that is tuned for high performance. De-normalization is a method to move from higher to lower normal forms of database modeling in order to speed up database access.