Relational division in information management

摘要

We present a unified framework for the management of stored data, decision models, and assertions in two-valued logic, based on the algebra of relations and on the operation of relational division. This powerful operation was developed in the context of stored data, and it also has limited applicability to models and assertions. The strength and weakness of division is that it allows universal quantification of certain queries on partitioned relations. We extend this concept by introducing a new operation, relational pseudodivision, which replaces universal with existential quantification and thus enlarges the set of available partitioning operations.