An integrated approach to teaching of abstract query languages and their implementations (abstract only)
Rajshekhar Sunderraman · 2014
The treatment of abstract query languages such as Relational Algebra, Relational Calculus, and Datalog in introductory database courses varies considerably across the various computer science departments around the world. We propose an integrated approach in which students learn how to express a natural language query in Domain Relational Calculus (DRC), apply a query-transforming algorithm to the DRC expression tree to produce Datalog Rules (DLG), and finally apply another query-transforming algorithm to the DLG rules to produce an equivalent Relational Algebra (RA) expression. This systematic approach works very well for "forall-queries" in which the forall-quantifier is necessary in the DRC expression. To make this approach even more effective, the students are required to use DRC, DLG, and RA interpreters that allow them to execute query expressions as well as produce equivalent expressions. The students are also involved in implementing these interpreters to get a deeper understanding of querying in relational systems.