University of Tuzla
Federated databases are useful in data integration, because they can provide data from other databases, without physically merging that data. Prolog-based federated databases are based on predicate logic and use the Prolog system to generate results for queries. In this paper, the authors constructed two formal criterions that express that such a Prolog-based federated database is correct. They distinguish between strong correctness and weak correctness, for which they both provided a criterion. Furthermore, the criterions are based on a formal representation of the Prolog-based federated database in conjunction with a non-Prolog based federated database.