In this paper, we introduce a novel approach to deductive databases meant to take into account the needs of current applications in the area of data integration. To this end, we extend the formalism of standard deductive databases to the context of Four-valued logic so as to account for unknown, inconsistent, true or false information under the open world assumption. In our approach, a database is a pair (E,R) where E is the extension and R the set of rules. The extension is a set of pairs of the form (f, v) where f is a fact and v is a value that can be true, inconsistent or false - but not unknown (that is, unknown facts are not stored in the database). The rules follow the form of standard Datalog{neg} rules but, contrary to standard rules, their head may be a negative atom. Our main contributions are as follows: (i) we give an expression of first-degree entailment in terms of other connectors and exhibit a functionally complete set of basic connectors not involving first-degree entailment, (ii) we define a new operator for handling our new type of rules and show that this operator is monotonic and continuous, thus providing an effective way for defining and computing database semantics, and (iii) we argue that our framework allows for the definition of a new type of updates that can be used in most standard data integration applications.
Inductive Logic Programming in Databases: from Datalog to DL+log
Università degli Studi di Bari（巴里大学）
在本文中，我们解决了一个问题，已经引起了数据库社区的注意，随着语义Web的出现，即本体论（和它们所传达的语义）如何帮助解决典型的数据库问题的问题，通过更好地了解KR方面相关的数据库。特别是，我们调查这个问题，从ILP的角度考虑两个数据库的问题，（i）的定义的意见和（ii）的定义的约束，为数据库的模式表示也通过本体。两者都可以重新表述为ILP问题，并可以受益于KR框架DL+log的表达和演绎能力。我们通过实例说明了应用场景。关键词：归纳逻辑程序设计，关系数据库，本体，描述逻辑，混合知识表示和推理系统。逻辑程序设计理论与实践（Theory and Practice of Logic Programming，TPLP）
Experimenting with recursive queries in database and logic programming systems
Università della Calabria（卡拉布里亚大学）
本文考虑了大量（可能是分布式的）数据的推理问题。目前，现有的建议显示出一些局限性：{ \em（i）}由于推理通常在主存中进行的事实，可以同时处理的数据的量是有限的; { \em（ii）}与外部的交互（和独立的）DBMS不是微不足道的，在某些情况下，根本不允许;{ \em（iii）}当前实现的效率对于它们在涉及大量数据的复杂推理任务中的利用仍然是不够的。本文提供了在这种情况下的贡献，它提出了一个新的系统，称为DLV $^{DB}$，旨在解决这些问题。此外，本文报告了一个彻底的实验分析的结果，我们已经进行了比较我们的系统与几个国家的最先进的系统（包括逻辑和数据库）的一些经典的演绎问题;其他测试系统是：LDL++，XSB，Smodels和三个顶级的商业DBMS。DLV $^{DB}$在递归查询上的性能甚至明显优于商业数据库系统。逻辑程序设计理论与实践（Theory and Practice of Logic Programming，TPLP）
ACE: A Cardinality Estimator for Set-Valued Queries
University of New South Wales（新南威尔士大学）；The University of Auckland（奥克兰大学）；The Chinese University of Hong Kong, Shenzhen（香港中文大学（深圳））；The University of Melbourne（墨尔本大学）；Aalborg University（奥尔堡大学）
