Knowledge Representation using Schema Tuple Queries

This paper introduces schema tuple queries and argues for their suitability in representing knowledge over standard relational databases. Schema tuple queries are queries that return only whole tuples of schema relations. In particular a subclass of the schema tuple queries is identified that is decidable for satisfiability and is closed over syntactic query difference. These properties enable the determination of query containment, equivalence and disjointness. Given this, the identified query class possesses many of the desirable properties of description logics. Additionally such schema tuple queries may be directly translated to SQL and applied over standard n-ary database relations.