Candidate Keys, Essay Example

The unique information of the entities has always played a pivotal role in society. One constantly faces with invoice numbers and costumer IDs that bear some unique information about their owner – whether it is a person, a company or a whole country. In the article “Candidate keys: Choosing the right primary key”, Pederson (2004) states that there are three demands on each candidate key, and choosing the primary key is the main task in the creation of the unique information in a database model.

According to the author “names are not unique”, but each person should possess a unique candidate key helpful in his/her identification not to mislead an employee, a company or other entities. In this context, the necessity of a primary key is obvious; one of the principal requirements for a unique primary key is the absence of null values. In the result of the author’s investigation in a situation with a database system, he claims that serious database systems will reject the individuals’ attempts to go further on that path (Pederson, 2004). In addition, he states that the properties of a primary key should not change. As his research shows, there are international adopted standards for naming countries. ISO operates different names of the same countries; e.g. USSR became Russia that has several standard names nowadays: RUS, RS and RU. So one can not be sure with what country he/she deals with (Pederson, 2004).  Thus, the uniqueness, the absence of null values, and the permanence are three main properties of a primary key.

One more idea the author voices in his article is that “…three fundamental demands on the candidate keys that we must never deviate from, if it is to become the subject for a primary key” (Pederson, 2004). It seems to be the correct statement, because it is extremely important for each primary key to carry the unique information, to be valuable and permanent. These features help to distinguish various individuals and entities. There are many coding systems in the modern world; hence the process of primary key generation acquires exclusive significance.

Reference

Pederson, A. (2004). Candidate keys: Choosing the right primary key. Oracle FAQ’s Web site. Retrieved November 13, 2010, from http://www.orafaq.com/node/24