Managing Semistructured Data with FLORID: A
Deductive Object-Oriented Perspective
Bertram Ludäscher, Rainer Himmeröder, Georg Lausen,
Wolfgang
May, Christian Schlepphorst
Abstract.
The closely related research areas management of semistructured
data and languages for querying the Web have recently
attracted a lot of interest. We argue that languages supporting
deduction and object-orientation (DOOD languages) 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 well, since the latter may be viewed as
(very simple) instances of the former. Deductive rules
provide a powerful framework for expressing complex queries in a
high-level, declarative programming style.
We elaborate on the management of semistructured data and show how
reachability queries involving general path expressions and the
extraction of data paths in the presence of cyclic data can be
handled. We then propose a formal model for querying structure and
contents of Web data and present its declarative semantics. A main
advantage of our approach is that it brings together the
above-mentioned issues in a unified, formal framework and--using the
FLORID system--supports rapid prototyping and experimenting with all
these features. Concrete examples illustrate the concise and elegant
programming style supported by FLORID and substantiate the
above-mentioned claims.
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