Concept based querying of semistructured data

Abstract

In the last years, semistructured data has played an increasing role within the database community. Many query languages have been developed for querying semistructured data and in particular XML data sources. XML data often is described by means of DTDs and more recently through XML schemas. This paper is about querying semistructured data by making use of the schema and the types described therein. Elements of an XML documents are considered as instances of schema concepts. Concept based queries provide a means to retrieve instances based on concept names and in particular offer a possibility to exploit generalization relationships between concepts. As a consequence, concept based queries free users from knowing the details about the structure in XML documents and hence ease querying of semi structured data.