by Ivan C
Normalizing a database requires removing redundancies of the data. A raw database is considered to be a database that has the same data in one or more tables. Some problems that occur with this is security risks, disk space usage, queries speed, update efficiencies, and data integrity. The logical design aspect of a database should try to completely remove any data redundancy. It should be designed keeping the end user into consideration with simplicity and ease of use. Some examples of end user considerations include
· What data should be stored in the database?
· How will the user access the database?
· What privileges does the user require?
· How should the data be grouped in the database?
· How is all data related in the database
By having duplicate data confusion can occur. An address can be stored twice for the same employee but could be different in each table. By having a single table hold the address it could prevent time being wasted to confirm the actual table. The most common normal forms in normalization include the first normal form, second normal form, and third normal form. The goal of the first normal form is to divide data into tables. In the second normal form data that is found partially dependent on the primary is set in another table. Finally the third normal form requires data that is not dependent on the primary key to be removed. Normalizing a database improves database organization, reduces redundant data, creates a more flexible database design, better database security, and keeps data consistent (Plew & Stephens, 2003). Although normalizing a database have many benefits it does have some disadvantages. A normalized database, compared to denormalized, must find requested tables and link tables to find desired data. Thus requiring more CPU, memory, and input/output (Plew & Stephens, 2003). Only time a database would be dernormalized would be to increase its performance, but not to the state where it is a database that has not been normalized. For example from third normal form to second normal form. Doing so would require less CPU and input/output.
Overall this article reinforces what is being taught in class. It adds the extra knowledge and detail about normalization. This article explained the disadvantages and disadvantages of normalization very well. I found interesting how it explained why denormalization would be necessary in some scenarios. Although this article had good information it had examples that I did not understand. The examples being explained were in SQL which I do now know. The article was easy to read and was organized well by subject. It explained data redundancy, naming conventions, referential integrity, and denormalization of a database
Plew, R., & Stephens, R. (2003, January 24). informIT. Retrieved October 22, 2011, from http://www.informit.com/articles/article.aspx?p=30646