Normalization of Relations with Nulls in Candidate Keys

Normalization of Relations with Nulls in Candidate Keys

George C. Philip (University of Wisconsin-Oshkosh, USA)
Copyright: © 2002 |Pages: 11
DOI: 10.4018/jdm.2002070103
OnDemand PDF Download:
$37.50

Abstract

This paper discusses normalization of relations when the candidate keys of a relation have missing information represented by nulls. The paper shows that when the missing information is of the type “not applicable” or “does not exist,” problems and confusion can arise in normalizing relations. Candidate keys with missing information commonly are found in relations that represent information on two entities with a one-to-one relationship between them. The current definition of Boyce-Codd Normal Form (BCNF) is ineffective in identifying poor designs in such relations that may have insertion/deletion anomalies. It is shown that the above problem can be corrected by incorporating the concept of entity integrity rule into the definition of BCNF. This paper also shows that incorporating the entity integrity rule into the definition of either a relation or a candidate key does not provide a satisfactory solution to the problem.

Complete Article List

Search this Journal:
Reset
Open Access Articles: Forthcoming
Volume 28: 4 Issues (2017): Forthcoming, Available for Pre-Order
Volume 27: 4 Issues (2016): 2 Released, 2 Forthcoming
Volume 26: 4 Issues (2015)
Volume 25: 4 Issues (2014)
Volume 24: 4 Issues (2013)
Volume 23: 4 Issues (2012)
Volume 22: 4 Issues (2011)
Volume 21: 4 Issues (2010)
Volume 20: 4 Issues (2009)
Volume 19: 4 Issues (2008)
Volume 18: 4 Issues (2007)
Volume 17: 4 Issues (2006)
Volume 16: 4 Issues (2005)
Volume 15: 4 Issues (2004)
Volume 14: 4 Issues (2003)
Volume 13: 4 Issues (2002)
Volume 12: 4 Issues (2001)
Volume 11: 4 Issues (2000)
Volume 10: 4 Issues (1999)
Volume 9: 4 Issues (1998)
Volume 8: 4 Issues (1997)
Volume 7: 4 Issues (1996)
Volume 6: 4 Issues (1995)
Volume 5: 4 Issues (1994)
Volume 4: 4 Issues (1993)
Volume 3: 4 Issues (1992)
Volume 2: 4 Issues (1991)
Volume 1: 2 Issues (1990)
View Complete Journal Contents Listing