Converging to the chase - A tool for finite controllability

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• 作者：Tomasz Gogacz ; ^{gogo@cs.uni.wroc.pl" class="auth_mail" title="E-mail the corresponding author} ; Jerzy Marcinkowski ; ^{jma@cs.uni.wroc.pl" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Tuple generating dependencies ; Sticky Logic ; Finite controllability ; Bounded Derivation Depth Property
• 刊名：Journal of Computer and System Sciences
• 出版年：2017
• 出版时间：February 2017
• 年：2017
• 卷：83
• 期：1
• 页码：180-206
• 全文大小：767 K

文摘

We solve a problem, stated in [5], showing that Sticky Datalog^∃, defined in the cited paper as an element of the Datalog^± project, has the Finite Controllability property, which means that whenever a query Ψ is not logically implied by a set of atoms D$\mathbb{D}$ and a Sticky Datalog^∃ theory T$\mathcal{T}$ a finite structure M   can be found such that M⊨D,T$M\models \mathbb{D},\mathcal{T}$, but M⊭Ψ$M⊭\mathrm{\Psi }$. In order to do that, we develop a technique, which we believe can have further applications, of approximating Chase(T,D)$Chase(\mathcal{T},\mathbb{D})$, for a database instance D$\mathbb{D}$ and a set of tuple generating dependencies and Datalog rules T$\mathcal{T}$, by an infinite sequence of finite structures, all of them being models of T$\mathcal{T}$ and D$\mathbb{D}$.