Database Schema Functional Dependency Entity-Relationship Model Functional Constraint Reasoning Method
Issue Date:
2009
Publisher:
Institute of Mathematics and Informatics Bulgarian Academy of Sciences
Citation:
Serdica Journal of Computing, Vol. 3, No 2, (2009), 179p-204p
Abstract:
Current methods of database schema design are usually based
on modeling the real world as entity (or object) classes with relationships
among them. Properties of relationships can be described by semantical
database constraints. One of them is functional dependency, which has a
key role in traditional database design. The three basic types of binary relationships
that can be described by functional dependencies are one-to-one,
one-to-many and many-to-many. They can also be expressed by common
graphical languages like the Entity-Relationship (ER) graph. However, relationships
defined among more than two entity classes (ternary, quaternary,
etc.) are usually not investigated and the common graphical tools lack expressive
power regarding them. We show that the variety of relationship
types is rich for higher arities and propose a simplified formalism for functional
constraints as well as graphical and spreadsheet reasoning methods for
handling sets of functional constraints that also help by relationship design.
Description:
This work is supported by the Hungarian Scientific Research Fund (OTKA), grant T042706.