Brief Announcement: Extending SQL Access Control to Derived and Distributed Data

Access-control mechanisms in distributed systems can differ greatly. For example, a data warehouse materializes a separate database; the underlying source administrators then grant full privileges on their contributed data to the warehouse administrator, trusting that he will grant appropriate privileges on the warehouse data. On the other hand, federated database researchers have source and federation administrators collaborating to specify the rights of federation users. Research papers have proposed access-control models specifically for federations, distributed-object systems, XML systems, etc. These proposed models, although academically interesting, are neither easy for administrators to use nor attractive for vendors to implement. Our approach is to extend SQL in three ways: • inferred privileges on derived data; • privileges for use in constructing derived data; • factored privileges, to model different execution concerns. By combining these features, we can represent many policies specifiable in other researchers ’ models, with significantly simpler administration and implementation. We explain these three components of our model via a running example; refer to the full paper for details [RS]. Consider a national network of hospitals, each having the local table