Why would a database be denormalized?

A.
To ensure data integrity.

B.
To increase processing efficiency.

C.
To prevent duplication of data.

D.
To save storage space.

Explanation:
Denormalization is the process of attempting to optimize the performance of data storage by adding
redundant data. It is necessary because current DBMSs are not fully relational. A fully relational
DBMS would be able to preserve full normalization at the logical level, while allowing it to be
mapped to performance-tuned physical level. Database designers often justify denormalization on
performance issues, but they should note that logical denormalization can easily break the
consistency of the database, one of the all-important ACID properties. However, a designer can
achieve the performance benefits while retaining consistency by performing denormalization at a
physical level; such denormalization is often called caching.