A Deductive Database with Datalog and SQL Query Languages

摘要

This paper introduces Datalog Educational System (DES). a deductive database which supports both Datalog and SQL as query languages. Since its inception, this system is targeted to educational purposes rather to develop an efficient, competitive system with respect to other existing systems. As distinguishing features, it is free, open-source, multiplatform, interactive, portable, GUI-enabled, implemented following ISO-Prolog and supports extensions to pure Datalog in the form of stratified negation, strong constraints, types, metapredicates. and duplicates. Also, test case generation for SQL views and declarative debugging for Datalog programs and SQL views are supported. SQL statements, following ISO standard, are compiled to Datalog programs and solved by its inference engine. Nonetheless, ODBC connections are also supported, which enables access to external DBMSs and benefit from their solving performance, persistency and scalability.