Modeling semantic constraints with logic in the EARL data model

The authors present a portion of the EARL semantic data model, an augmentation of the entity-relationship model, which uses notational constructs based on propositional logic to allow a greater selection of semantic integrity constraints to be captured during the specification and design of a domain schema. The use of these logic-based constructs is shown to allow more subtle constraints to be specified, so that ambiguity can be reduced when placing constraints on the universe of discourse for database or knowledge-base applications. The notion of what are semantic constraints is discussed, and notational constructs with informal semantics are defined for the EARL model. Several examples are presented