When Entities Are Types: Effectively Modeling Type-Instantiation Relationships

摘要

Type-instantiation relationships (TIRs) appear in many application domains including RFID-based inventory tracking, securities markets, health care, incident-response management, travel, advertising, and academia. For example an emergency response (type) is instantiated in the actual incident, or an advertisement (type) serves impressions on a website. This kind of relationship has received little attention in literature notwithstanding its ubiquity. Conventional modeling does not properly capture its underlying semantics. This can lead to data redundancy, denormalized relations and loss of knowledge about constraints during implementation. Our work formally defines and discusses the semantics of the type-instantiation relationship. We also present an analysis of how TIRs affect other relationships in a conceptual database schema, and the relational implications of our approach.