Denormalization: The process of transforming normalized relations into un-normalized relations to improve the efficiency of data processing.
Combine attributes from several relations together into one physical record.
Partition a relation or a table into several relations.
Replication of data
•Drawback of de-normalization
Reintroduce redundancies or anomalies into the system
•Increase a chance of errors and inconsistencies.
•Lead to more storage space.
Become useless if the frequencies of processing activities change.