Making a Federated System Active

A Federated Database System consists of autonomous component database systems that participate in the federation to allow controlled sharing of their data. It usually provides a global integrated view, a federated schema, that describes data stored in the component database systems. A very important aspect for this type of systems is to maintain the autonomy of the components while preserving the correct semantics of the federated schema. In order to achieve this goal we propose a system that responds automatically to design changes made in a component database, that affect the federated schema, without user intervention. Further, our system provides each component that decides to participate in a federation with the opportunity to choose between assuming the default control offered to it, or customizing the control by defining declaratively the system responses. Both cases rely on the use of Event-Condition-Action rules supported by the system. We also present a federated system architecture in which this system is a component.