文档介绍：View-based Query Answering in Description Logics:
Semantics plexity
Diego Calvanesea, Giuseppe De ob,
Maurizio Lenzerinib, ardo Rosatib
aKRDB Research Centre, Free University of Bozen-Bolzano
Piazza Domenicani 3, I-39100 Bolzano, Italy
bDipartimento di Informatica e Sistemistica, Sapienza Universit`adi Roma
Via Ariosto 25, I-00185 Roma, Italy
Abstract
View-based query answering is the problem of answering a query based only
on the puted answers to a set of views. While this problem has been
widely investigated in databases, it is largely unexplored in the context of De-
scription Logic ontologies. Differently from traditional databases, Description
Logics may express several forms of plete information, and this poses chal-
lenging problems in characterizing the semantics of views. In this paper, we first
present a general framework for view-based query answering, where we address
the above semantical problems by providing two notions of view-based query
answering over ontologies, all based on the idea that the puted answers
to views are the certain answers to the corresponding queries. We also relate
such notions to privacy-aware access to ontologies. Then, we provide decidabil-
ity results, algorithms, and plexity characterizations for view-based
query answering in several Description Logics, ranging from those with limited
modeling capability to highly expressive ones.
1. Introduction
View-based query processing is the problem of processing a query under
the assumption that the only accessible extensional information consists of the
puted answers to a set of queries, called views. Several articles in the
literature point out that this problem [1, 2, 3] is relevant in many aspects of
information management, including query optimization, data warehousing, data
integration, and query answering with plete information. In all these
contexts, the problem arises of answering a query posed to a database only on
the basis of the informa