An object model of data, based on the ODMG industry standard for database applications

摘要

The computational requirements of modern information systems, coupled with the inherent limitations of the relational databases, are stimulating research into post-relational database systems. The recent advances in object databases resulting from the integration of object-oriented programming capabilities with database capabilities, seem highly promising. The Object Database Management Group (ODMG) as part of the Object Management Group (OMG) has proposed a de facto standard known as ODMG-93 for object databases, which is rapidly gaining acceptance. The author introduces the relevant aspects of the object technology within the OMG framework, their Common Object Request Broker Architecture (CORBA), and discusses how this technology integrates with, and extends the client-server model. The author surveys the main elements of ODMG data model, particularly the datatypes supported, and introduces the elements of both, ODL (Object Definition Language) for defining the structure of the database, and OQL (Object Query Language) for defining queries over the database. Finally, some results are highlighted from the author's work on a calculus for the declarative representation of the OQL queries, suitable for an efficient implementation.