A schema-based approach to modeling and querying WWW data

The steady growth of the amount of data published on the World Wide Web has led to a number of attempts to provide effective Web querying, as a complement to conventional navigation techniques. In this paper, we propose to support WWW querying by specifying both logical and navigational aspects of a Web site through the unifying notion of schema. Schemata are a powerful tool for classifying and maintaining WWW data as well as for semantics-aware search on the Web. Moreover, schema availability is the basis for an effective flexible querying mechanism. Following the style of such languages as Good and G-Log, the WG-Log language described in the paper uniformly represents site schemata, instances and queries as graphs. Gracefully supporting schemata that are huge or subject to change, WG-Log adequately represents data whose structure is less rigid than that of traditional databases; moreover, it allows for a uniform representation of flexible queries and views, the latter expressing customized access structures to the site information.