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CORR
2011
Springer

Rewriting Ontological Queries into Small Nonrecursive Datalog Programs

13 years 2 months ago
Rewriting Ontological Queries into Small Nonrecursive Datalog Programs
Abstract. We consider the setting of ontological database access, where an Abox is given in form of a relational database D and where a Boolean conjunctive query q has to be evaluated against D modulo a T-box Σ formulated in DLLite or Linear Datalog± . It is well-known that (Σ, q) can be rewritten into an equivalent nonrecursive Datalog program P that can be directly evaluated over D. However, for Linear Datalog± or for DL-Lite versions that allow for role inclusion, the rewriting methods described so far result in a nonrecursive Datalog program P of size exponential in the joint size of Σ and q. This gives rise to the interesting question of whether such a rewriting necessarily needs to be of exponential size. In this paper we show that it is actually possible to translate (Σ, q) into a polynomially sized equivalent nonrecursive Datalog program P.
Georg Gottlob, Thomas Schwentick
Added 19 Aug 2011
Updated 19 Aug 2011
Type Journal
Year 2011
Where CORR
Authors Georg Gottlob, Thomas Schwentick
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