Virtual Integration of Distributed Database by Multiple Agents

Since the Internet becomes popular and widely used, many services including databases are available for users. However, more databases are available, more difficult it becomes to select and use them. One promising way to solve this problem is to use a software agent called Mediator (or Facilitator) [1]. A mediator has meta-information of databases, and it can select databases that satisfy requests from users, access them in suitable protocols, and summarize their answers. Users have only to know the way to access the mediator. From the view of users, a mediator realizes the virtual integration of distributed databases