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Schlagwörter:
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Zusammenfassung:
We aim to demonstrate that automated deduction techniques, in particular those
following the model computation paradigm, are very well suited for database
schema/query reasoning. Specifically, we present an approach to compute
completed paths for database or XPath queries. The database schema and a query
are transformed to disjunctive logic programs with default negation, using a
description logic as an intermediate language. Our underlying deduction system,
KRHyper, then detects if a query is satisfiable or not. In case of a
satisfiable query, all completed paths – those that fulfill all given
constraints – are returned as part of the computed models.
The purpose of computing completed paths is to reduce the workload on a query
processor. Without the path completion, a usual XPath query processor would
search the whole database for solutions to the query, which need not be the
case when using completed paths instead.
We understand this paper as a first step, that covers a basic schema/query
reasoning task by model-based deduction. Due to the underlying expressive logic
formalism we expect our approach to easily adapt to more sophisticated problem
settings, like type hierarchies as they evolve within the XML world.