Dbm380 Week 4 Normalization

Normalization of a Database

DBM/380

June 8, 2011

Normalization of a Database

Normalization is a process of rearranging a database so that it is placed in a standard form that prevents anomalies. Anomalies that are prevented include duplicated data, incorrectly associating two pieces of unrelated data so that you cannot delete one without deleting another, require a piece of data that should not exist in order to represent a piece of data that should exist, and limit the number of values that you can use for what should have been a multi-valued piece of data (Stephens, 2009).

“A relation is in third normal form if it is in SecondNormalForm and there are no functional (transitive) dependencies between two (or more) non-primary key attributes” (C2.com, 2009). Functional dependencies on non-key fields are eliminated by putting them in a separate table. At this level, all non-key fields are dependent on the primary key.

A row is in third normal form if and only if it is in second normal form and if attributes that do not contribute to a description of the primary key are moved into a separate table. An example is creating look-up tables (psoug.org, 2009).

A lot of database designers stop normalizing at 3NF because it provides the most bang for the buck (Stephens, 2009). It is reasonably easy to convert a database to 3NF and at this level of normalization, prevents the most common forms of data anomalies. It stores separate data separately so you can add and remove pieces of information without destroying unrelated data. It also removes redundant data so that the database is not full of several copies of the same information that could waste space and make updating the values very difficult (Stephens, 2009).

References

C2.com. (2009, January 6). Third Normal Form. Retrieved from http://c2.com/cgi/wiki?ThirdNormalForm

Stephens, R. (2009). Beginning Database Design Solutions (Rev ed.). Indianapolis, ID: John Wiley & Sons Inc..

psoug.org. (2009, May 28)....