A Survey on Disk Oriented Querying and Reasoning on the Semantic Web

This paper presents a description of seven systems, which use database technology to both represent knowledge persistently and make scalable queries on it, in the Semantic Web context. From the study of these systems we can deduce that a lot of work regarding massive storage of knowledge has already been carried out. We can observe an evolution from RDF to OWL in most up-to-date systems. The analyzed approaches carry out a mapping between the (structure of the) ontology and the data model of the persistence management system. Nevertheless, there is still considerable work to be done regarding efficient disk oriented Abox (ontology instances) querying and reasoning. We think that due to the Semantic Web features many problems related to assertional reasoning should be addressed. We also believe that the physical design of the knowledge base is a very important task, which includes the development of both specific storage structures and indexes for knowledge storage and retrieval.