Object Discovery and Unification in

Federated Database Systems?

Joachim Hammer, Dennis McLeod and Antonio Si

Computer Science Department

University of Southern California

Los Angeles, CA 90089-0781, USA

fjoachim,mcleod,asig@cs.usc.edu

Abstract

A key challenge in sharing-oriented information management environments, such as networks of heterogeneous, autonomous database systems, is to provide capabilities to allow information units and resources to be flexibly and dynamically combined and interconnected, while at the same time preserving the investment in and the autonomy of each individual component. The research described here specifically focuses on two key aspects of this: (1) how to discover the location and content of relevant, nonlocal information units, and (2) how to identify and resolve the semantic heterogeneity that exists between related information in different database components. Our approach serves as a basis for the sharing of related concepts through partial meta-data (conceptual schema) unification without the need for a global view of data. We demonstrate and evaluate our approach using the Remote-Exchange experimental prototype system [5], which supports information sharing and exchange from the above perspective.

1 Introduction

Support for interoperability among autonomous, heterogeneous data/knowledge base systems is emerging as a key information management problem for the 1990s. Cooperative work, computer-based manufacturing, scientific databases, and traditional data processing are only a few of the environments where collaboration among the individual systems is desired [17, 19, 24]. Proposed architectures to address the interoperability problem range from tightly coupled composite approaches in which individual databases are integrated into a centralized global database [1], to loosely coupled federated environments wherein

?This research was supported in part by NSF grant IRI-9021028.