Database De-Centralization - A Practical Approach

We describe a scheme to fragment and distribute centralized databases. ’ The problem is motivated by trends towards down-sizing and reorganization, reflecting actual, often distributed responsibilities within companies. A major practical requirement is that existing application code must be left unchanged. We present SQL extensions to specify ownership and data replication information declaratively. From this, a compiler generates triggers and view definitions that implement the distributed scheme, on top of a collection of local databases. Our strategy has been applied successfully at Telenor the Norwegian telephone comp.any.