Construetor set´s database support for knowledge based systems

Current database systems provide only rather limited tools for advanced applications, for example for the database support of knowledge based systems. Especially, it is not possible to represent recursive rules which are denned on the basis of stored data (facts). Using the terminology of PROLOG, this means that database systems provide means for managing facts, but rules are not supported. The semantic gap, therefore, between conventional database systems on the one hand and knowledge base management systems on the other is too large. This paper presents new tools, based on a database programming language, which allow the support of rules on the basis of existing relations. These rules may be recursive, thus providing similar mechanisms as PROLOG does. The tools are set oriented, they allow, therefore, an efficient implementation. Moreover, some disadvantages of PROLOG are avoided, for example infinite recursion. In addition, data types are defined for the representation of updatable rule bases thus providing a first step towards integrated fact and rule management using relational technology.