Standard Transformations for the Normalization of ER Schemata

Normalization, which makes up the core of the design theory for relational databases, is also considered an important technique to improve the quality of ER schemata. For ER schemata, however, local normalization based on standard transformations is better suited than a global approach similar to that used by relational normalization algorithms. We first present a framework for describing ER schema transformations. Then a normal form, ER-BCNF, is defined which corresponds to BCNF, and a complete set of transformations to achieve this normal form is suggested. The question how null values should be dealt with is raised afterwards. Finally, we discuss how the theory may be applied and give an outlook on future research.

[1]  Otto Rauh.  ERMded– eine Erweiterung des Entity-Relationship-Modells zur Modellierung deduktiver Informationssysteme , 1995, Informatik Forschung und Entwicklung.

[2]  David Maier,et al.  The Theory of Relational Databases , 1983 .

[3]  Isamu Kobayashi,et al.  Losslessness and semantic correctness of database schema transformation: another look of schema equivalence , 1986, Inf. Syst..

[4]  Jean-Luc Hainaut,et al.  Schema Transformation Techniques for Database Reverse Engineering , 1993, ER.

[5]  Sushil Jajodia,et al.  The Problem of Equivalence for Entity-Relationship Diagrams , 1983, IEEE Transactions on Software Engineering.

[6]  Otto Rauh,et al.  Modeling deductive information systems using ERMded , 1996, Decis. Support Syst..

[7]  Shamkant B. Navathe,et al.  Conceptual Database Design: An Entity-Relationship Approach , 1991 .

[8]  Michael Adamowicz,et al.  Data base systems , 1976 .

[9]  Peter P. Chen,et al.  A Decomposition of Relations Using the Entity-Relationship Approach , 1981, ER.

[10]  Jeffrey D. Ullman,et al.  Principles Of Database And Knowledge-Base Systems , 1979 .

[11]  Arnon Rosenthal,et al.  Theoretically Sound Transformations for Practical Database Design , 1987, ER.

[12]  Johann A. Makowsky,et al.  Entity-Relationship Consistency for Relational Schemas , 1986, ICDT.

[13]  Tok Wang Ling.  A Normal Form For Entity-Relationship Diagrams , 1985, ER.

[14]  Valeria De Antonellis,et al.  Relational Database Theory , 1993 .

[15]  Patrick Valduriez,et al.  Relational Databases and Knowledge Bases , 1989 .

[16]  Peter P. Chen.  The entity-relationship model: toward a unified view of data , 1975, VLDB '75.

[17]  Otto Rauh,et al.  Searching for Compositions in ER Schemes , 1993, ER.

[18]  Tok Wang Ling,et al.  An Analysis of Multivalued and Join Dependencies Based on the Entity-Relationship Approach , 1985, Data Knowl. Eng..

[19]  Henk Sol,et al.  Information Systems Design Methodologies: A Comparative Review , 1983 .