Generating on the fly queries for the semantic web: The ICS-FORTH graphical RQL interface (GRQL)

Abstract

Building user-friendly GUIs for browsing and filtering RDF/S description bases while exploiting in a transparent way the expressiveness of declarative query/view languages is vital for various Semantic Web applications (e.g., e-learning, e-science). In this paper we present a novel interface, called GRQL, which relies on the full power of the RDF/S data model for constructing on the fly queries expressed in RQL. More precisely, a user can navigate graphically through the individual RDF/S class and property definitions and generate transparently the RQL path expressions required to access the resources of interest. These expressions capture accurately the meaning of its navigation steps through the class (or property) subsumption and/or associations. Additionally, users can enrich the generated queries with filtering conditions on the attributes of the currently visited class while they can easily specify the resource's class(es) appearing in the query result. To the best of our knowledge, GRQL is the first application-independent GUI able to generate a unique RQL query which captures the cumulative effect of an entire user navigation session. © Springer-Verlag 2004.