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Evaluation of complex cardinality constraints

: Baumann, P.; Zhou, J.

Pernul, G.; Tjoa, A.M.:
Entity-relationship approach, ER '92. Proceedings : 11th International Conference on the Entity-Relationship Approach. Karlsruhe, Germany, October 7 - 9, 1992
Berlin: Springer, 1992 (Lecture Notes in Computer Science 645)
ISBN: 3-540-56023-8
ISBN: 0-387-56023-8
International Conference on the Entity-Relationship Approach <11, 1992, Karlsruhe>
Fraunhofer IGD ()
April; entity-relationship model; Relationship semantics; valence concept

In a previous paper, the valence concept, a general method to describe relationships, has been introduced along with a set-theoretic formal semantics. This approach is type-based, admits variants and detailed cardinality specifications, and can cope with incomplete intermediate states. Nevertheless, the resulting syntax is easy to understand. In this paper, an implementation of the valence concept is outlined. Special emphasis has been placed on minimizing space and time overhead on instant level, but it turns out that data dictionary overhead also keeps within reasonable limits. Please note that the valence concept is not a complete data model by itself, but a relationship model which can be embedded in a wide range of data models.