The object-oriented data model TM is a language that is based on the formal theory of FM, a typed language with object-oriented features such as attributes and methods in the presence of subtyping. The general (typed) set constructs of FM allow one to deal with (database) constraints in TM.The paper describes the theory of FM, and discusses the role that set expressions may play in conceptual database schemas. Special attention is paid to the treatment of constraints, and a three-step specification approach is proposed. This approach results in the formal notion of database universe stated as an FM expression.
['Herman Balsters', 'Rolf A. de By', 'Roberto Zicari']
Typed Sets as a Basis for Object-Oriented Database Schemas