Outer Joins in a Deductive Database System

Outer Joins in a Deductive Database System

Outer joins are extended relational algebra operations intended to deal with unknown information represented with null values. This work shows an approach to embed both null values and outer join operations in the deductive database system DES (Datalog Educational System), which uses Datalog as a query language. This system also supports SQL, where views and queries are compiled to Datalog prog...

DES: A Deductive Database System

This work describes a novel implementation of a deductive database system which fills some gaps other systems do not. In fact, this system was born to this end and since its inception, many new features have been added (null values, outer joins, aggregates, ...). In particular, it embodies both Datalog and SQL query languages, where the same database can be queried. It enjoys an actual interact...

The MyYapDB Deductive Database System

We describe the MyYapDB, a deductive database system coupling the Yap Prolog compiler and the MySQL DBMS. We use our OPTYap extension of the Yap compiler, which is the first available system that can exploit parallelism from tabled logic programs. We describe the major features of the system, give a simplified description of the implementation and present a performance comparison of using stati...

The Deductive Database System LOLA

Deductive Object-oriented Database System

DO is a deductive object oriented database developed at the National University of Singapore The system aims to integrate de ductive and object oriented paradigms and use their advantages to over come both the paradigms respective weaknesses DO di ers from con ventional deductive object oriented databases in its key based approach for OIDs pro active approach to resolving inheritance con icts a...