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Title: Reasoning Methods for Designing and Surveying Relationships Described by Sets of Functional Constraints
Authors: Demetrovics, János
Molnár, András
Thalheim, Bernhard
Keywords: 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.
ISSN: 1312-6555
Appears in Collections:Volume 3 Number 2

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