Merging heterogeneous security orderings

The problem of integrating multiple heterogeneous legacy databases is an important problem. Many papers <3,7,9] to date on this topic have assumed that all the databases comprising a mediated/federated system share the same security ordering. This assumption is often not true as the databases may have been developed independently by different agencies at different points in time. In this paper, we present techniques by which we may merge multiple security orderings into a single unified ordering that preserves the security relationships between orderings. We present a logic programming based approach, as well as a graph theoretical approach to this problem.