Graph-theoretical methods to construct entity-relationship databases

Abstract

Within the recent years, the entity-relationship approach has become one of the most popular methods in high-level database design. In this approach data are modelled as entity and relationship types. Usually relationship types come along with certain restrictions that influence the structure of databases. Cardinality constraints are the most commonly used class of constraints used to model such restrictions. Database instances satisfying given cardinality constraints are said to be valid. The aim of this paper is to show how to use methods from graph theory to determine the class cardinalities of entity and relationship types in valid databases. We develop algorithms for this purpose and a number of variations of the problem, namely to construct databases of minimum size and linear ternary databases.