A distributed object-oriented database system supporting shared and private databases

Abstract

ORION-2 is a commercially available, federated, object-oriented database management system designed and implemented at MCC. One major architectural innovation in ORION-2 is the coexistence of a shared databese and a number of private databases. The shared database is accessible to all authorized users of the system, while each private database is accessible to only the user who owns it. A distributed database system with a shared database and private databases for individual users is a natural architecture for data-intensive application environments on a network of workstations, notably computer-aided design and engineering systems. This paper discusses the benefits and limitations of such a system and explores the impact of such an architecture on the semantics and implementation of some of the key functions of a database system, notably queries, database schema, and versions. Although the issues are discussed in the context of an object-oriented data model, the results (at least significant portions thereof) are applicable to database systems supporting other data models.

A Federated Cooperation Architecture for Expert Systems Involved in Layout Optimization

“…Both the information and the control are distributed within the network. PEER does not define a single global schema on the shared information to support the entire network of database systems, unlike many other distributed object-oriented database systems (Kim et al, 1991). The interdependencies between two nodes' information are established through the schemas defined on their information; thus there is no need to store the data redundantly in different nodes.…”

“…At the level of the integrated schema, the physical distribution of information becomes hidden, and the contributing agents are no longer directly visible to the end user. Different agents can establish different correspondences between their own schema and other agents' schemas, and thus there is no single global schema for the network, unlike other "federated" database systems, such as in ORION2 (Kim et al, 1991), that define one global schema to support the entire network of agents.…”

Concept bases: A support to information systems integration

“…), and the relationships and rules existing between these elements. Generally, the data model chosen for this step is a semantic one (entity-relationship or object-oriented [15]). This preintegration step is justified, among others, by the relative semantics weakness of schemes and the heterogeneity of used data models.…”

Schema evolution and integration

“…The last implementation of ORION, ORION-2 [22], supported personal databases in association with a central public database. Personal subschema could be devloped but could not be defined in opposition to the information contained in the central (public) schema.…”