Resumen de From relational to deductive databases
This paper highlights the limits of current implementations of SQL and shows how they can be overcome with deductive approaches. Deductive query languages subsuming relational ones must include constructors to allow users for submitting queries semantically equivalent to their relational counterparts. As deductive languages are based on first order predicate logic, they are able to capture relational semantics, which involves negation. In addition to negation, as e.g. needed to express set difference, usual relational outer join statements and aggregate functions must be taken into account for such subsuming deductive languages. We base our presentation on the grounds of DES (Datalog Educational System), a deductive database system that integrates both deductive and relational database languages in a common inference engine and system.
