Abstract
A distributed database is a collection of data sources distributed across many computers. It is a single logical and centrally managed database stored in multiple physical locations. In order to access data locally and manage data globally, a good distributed database system (DDBS) that can supply reliable and up-to-date information is critical. A good DDBS should have functionalities such as providing users with timely and flexible access to information, providing DBA (database administrator) personnel with tools to analyze the data in a meaningful manner, and allowing the personnel to control the safety and integrity of the data. However, query processing in such a distributed database system is complicated. For example, some important issues are how to keep data up-to-date when it is physically dispersed, and how to propagate information to the whole DDBS when an update occurs. In response to these issues, we propose an expert query system that uses a Bayesian network as its framework to propagate information and to keep data up-to-date for a DDBS. The goal of this query system is to assist the DBA personnel in maintaining the data dynamically and to assist the users in accessing reliable and timely information.
