Advanced applications require construction, efficient access and management of large databases with rich data structures and inference mechanisms. However, such capabilities are not directly supported by the existing database systems. In this paper, we describe Relationlog, a persistent deductive database system that is able to directly support the storage, efficient access and inference of data with complex structures.

We describe the design and implementation of Relationlog, a persistent deductive database system. Unlike other related systems such as Aditi, CORAL, LDL, LOLA and Nail-Glue, Relationlog supports effective storage, efficient access and inference of large amounts of data with complex structures and provides declarative query language that can define recursive views involving complex data and also a declarative data manipulation language to update databases.

Administering and maintaining access control systems is a challenging task, especially in environments with complex and changing authorization requirements. A number of authorization logics have been proposed that aim at simplifying access control by factoring the authorization policy out of the hard-coded resource guard. However, many policies require the authorization state to be updated after a granted access request, for example to reflect the fact that a user has activated or deactivated a role. Current authorization languages cannot express such state modifications; these still have to be hard-coded into the resource guard. We present a logic for specifying policies where access requests can have effects on the authorization state. The logic is semantically defined by a mapping to Transaction Logic. Using this approach, updates to the state are factored out of the resource guard, thus enhancing maintainability and facilitating more expressive policies that take the history of access requests into account. We also present a sound and complete proof system for reasoning about sequences of access requests. This gives rise to a goal-oriented algorithm for finding minimal sequences that lead to a specified target authorization state. 1