Managing semistructured data with FLORID: A deductive object-oriented perspective

The closely related research areas management of semistructured data and la nguages for querying the Web have recently attracted a lot of interest. We argue that languages supporting deduction and object-orientation (DOOD lang uages) are particularly suited in this context: Object-orientation provides a flexible common data model for combining information from heterogeneous sources and for handling partial information. Techniques for navigating in object-oriented databases can be applied to semistructured databases as wel l, since the latter may be viewed as (very simple) instances of the former. Deductive rules provide a powerful framework for expressing complex querie s in a high-level, declarative programming style. We elaborate on the management of semistructured data and show how reachabi lity queries involving general path expressions and the extraction of data paths in the presence of cyclic data can be handled. We then propose a form al model for querying structure and contents of Web data and present its de clarative semantics. A main advantage of our approach is that it brings tog ether the above-mentioned issues in a unified, formal framework and-using t he FLORID, system-supports rapid prototyping and experimenting with all the se features. Concrete examples illustrate the concise and elegant programmi ng style supported by FLORID and substantiate the above-mentioned claims. ( C)1998 Elsevier Science Ltd. All rights reserved.