Semistructured graph-based databases have been proposed as well-suited stores for World-Wide Web data. Yet so far, languages for querying such data are too complex for casual Web users. Further, proposed query approaches do not take advantage of the interactive nature of typical Web sessions--users are proficient at iteratively refining their Web explorations. In this paper we propose a new model for interactively querying and searching semistructured databases. Users can begin with a simple keyword search, dynamically browse the structure of the result, and then submit further refining queries. Enabling this model exposes new requirements of a semistructured database management system that are not apparent under traditional database uses. We demonstrate the importance of efficient keyword search, structural summaries of query results, and support for inverse pointers. We also describe some preliminary solutions to these technical issues.
Mediation architecture is well suited for integrating data over the web. We explore the possibility of exploying TSIMMIS technology for this task. Specifically, we shall address the issues surrounding the construction of wrappers and mediators, the query capabilities of data sources, and the efficiency of query processing over the web.
After we learn to deal with heterogeneity in hardware systems, operating systems, communication protocols, database systems and data schemas, we are still faced with the problem that the meaning of the words also varies. We will sketch an approach we are developing to define methods that can resolve such differences for specific application contexts.