A pattern-based object calculus

Abstract

Abstract. Several object-oriented database management systems have been implemented without an accompanying theoretical foundation for constraint, query specification, and processing. The pattern-based object calculus presented in this article provides such a theoretical foundation for describing and processing objectoriented databases. We view an object-oriented database as a network of interrelated classes (i.e., the intension) and a collection of time-varying object association patterns (i.e., the extension). The object calculus is based on first-order logic. It provides the formalism for interpreting precisely and unifor/nly the semantics of queries and integrity constraints in object-oriented databases. The power of the object calculus is shown in four aspects. First, associations among objects are expressed explicitly in an object-oriented database. Second, the "nonassociation" operator is included in the object calculus. Third, set-oriented operations can be performed on both homogeneous and heterogeneous object association patterns. Fourth, our approach does not assume a specific form of database schema. A proposed formalism is also applied to the design of high-level object-oriented query and constraint languages.

A Formalization of ODMG Queries

“…Over the last years, quite a few attempts have been published that aim at providing clean formalizations for OQL, for instance (Bancilhon and Khoshafian 1989, Abiteboul and Kanellakis 1989, Straube 1991, Bertino, Negri, Pelagatti and Sbattella 1992, Kifer, Kim and Sagiv 1992, Kifer, Lausen and Wu 1993, Hohenstein and Engels 1992, Herzig and Gogolla 1994, Kamel, Wu and Su 1994, Fegaras and Maier 1995. However, only few of these integrate all concepts of the ODMG proposal into a single formal model.…”