Soft constraints and heuristic constraint correction in entity-relationship modelling

Abstract

In entity-relationship modelling, cardinality constraints impose restrictions on the number of occurrences of objects in relationships. If violations may appear, cardinality constraints should be treated as soft constraints rather than as integrity constraints. Nevertheless one often expects them to be satisfied at least in average or up to a small number of exceptions. These expectations may compete each other and cause new kinds of inconsistencies. We discuss how these inconsistencies can be detected and repaired. © Springer-Verlag Berlin Heidelberg 2003.