MATERIALIZATION

A new data abstraction, called Materialization, is introduced to model a situation that occurs frequently in the real world and has important implications for database design. Materialization is the relationship between two entity types, one that represents a conceptual object, for example, a TV Model, and one that represents its corresponding concrete objects, in this case, actual TV Sets. The materialization construct is formally defined and contrasted with other well-known data abstractions. Its design implications are presented in terms of the entity-relationship model and its translation into a relational model. Guidelines are offered for the proper employment of this relationship in database design methodologies, and a discussion is provided of why this constitutes an important data modeling construct.