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An Indexing Scheme for RDF and RDF Schema based on Suffix Arrays

The Semantic Web is a candidate for the next generation of the World Wide Web. It is anticipated that the number of metadata written in RDF (Resource Description Framework) and RDF Schema will increase as the Semantic Web becomes popular. In such a situation, demand for querying metadata described with RDF and RDF Schema will also increase, and therefore effective query retrieval of RDF data is important. To this end, we propose an indexing scheme for RDF and RDF Schema. In our (proposed) scheme, we first extract four kinds of DAGs (Directed Acyclic Graphs) from an RDF data, and extract all path expressions from the DAGs. Then, we generate four kinds of suffix arrays based on the path expressions. Using the indices, we can achieve efficient processing of query retrievals on RDF data including schematic information defined by RDF Schema (for example, classes and/or properties).