The model-assisted global query system for multiple databases in distributed enterprises
Waiman Cheung, Cheng Kai Hsu · ACM Transactions on Information Systems · 1996
Today's enterprises typically employ multiple information systems, which are independently developed, locally administered, and different in logical or physical designs. Therefore, a fundamental challenge in enterprise information management is the sharing of information for enterprise users across organizational boundaries; this requires a global query system capable of providing on-line intelligent assistance to users. Conventional technologies, such as schema-based query languages and hard-coded schema integration, are not sufficient to solve this problem. This article develops a new approach, a “model-assisted global query system,” that utilizes an on-line repository of enterprise metadata—the Metadatabase—to facilitate global query formulation and processing with certain desirable properties such as adaptiveness and open-systems architecture. A definitional model characterizing the various classes and roles of the required metadata as knowledge for the system is presented. The significance of possessing this knowledge (via a Metadatabase) toward improving the global query capabilities available previously is analyzed. On this basis, a direct method using model traversal and a query language using global model constructs are developed along with other new methods required for this approach. It is then tested through a prototype system in a computer-integrated manufacturing (CIM) setting.