Artículo:

Formal Relational Languages in a Deductive Setting

The relational data model coincides with the deductive one and, thus, formal relational query languages can be mapped to a deductive setting. These languages include, on the one hand, Tuple Relational Calculus (TRC) and Domain Relational Calculus (DRC). It can be argued that TRC can be seen as the formal basis of SQL, while DRC does the same for the semantic web language SPARQL and even the graphical relational language Query-by-Example (QBE). On the other hand, Relational Algebra (RA) is also used as a target language for intermediate compilations from SQL to executable query plans. As commonly acknowledged, RA allows a more formal setting for query optimizations than SQL. In this work, we describe the new support of TRC and DRC in the deductive system DES (which included already SQL and RA) with the aim to have an integrated system for learning database query (formal) languages based on logic.