The logic of consistent query answering in database

由于几个原因，数据库可能包含不一致的信息，即参与违反某些完整性约束的信息。申请人和合著者已经将一致性数据表征为在原始数据库的一致性的最小形式的恢复下不变的数据。这个想法是在不必清理给定数据库的情况下对该一致信息进行计算访问，并尽可能避免计算和查询数据库的替代一致版本（修复）的昂贵操作。相反，该方法包括在查询时检索一致的，语义正确的信息。虽然在这一领域取得了许多进展，但在这一研究领域仍然存在一些概念和技术上的问题。我们将在这个项目中解决的一些问题如下：（a）开发，在语义和操作方面，逻辑控制推理和数据库中的一致性数据，一致的查询回答，特别是。(b)在这种情况下，处理缺乏完整信息的问题。(c)可以组合以前（chached）一致的结果，以便一致地回答更复杂的查询，并在此过程中使用辅助视图。(d)处理必须被视为数值属性的数值属性，而不是一般的数据属性。(e)虚拟数据集成系统中容易违反全局约束的复杂查询的一致响应。(f)在非关系数据库中的一致性查询应答，例如XML，RDF。(g)对等点之间数据的一致交换等。

For several reasons databases may contain inconsistent information, i.e. that participates in the violation of certain integrity constraints. The applicant and coauthors have characterized the consistent data as the one that is invariant under minimal forms of restoration of the consistency of the original database. The idea is to have computational access to this consistent information without having to clean the given database, and avoiding as much as possible the costly operation of computing and querying the alternative consistent versions of the database (the repairs). Rather, the approach consists in retrieving the consistent, semantically  correct information at query time. Although many progresses have been made in this area, there are still several conceptual and technical open problems in this line of research. Some of those we will address in this project are the following: (a) Developing, in semantic and operational terms, the logic that governs reasoning with and about consistent data in databases, and consistent query answering, in particular. (b) Dealing with absence of complete information in this context. (c) Possibility of composing previous (chached) consistent results in order  to consistently answer more complex queries, and the use of auxiliary views in this process. (d) Dealing with numerical attributes that have to be treated as such, as opposed to generic datatypes. (e) Consistent answering of complex queries in virtual data integration systems that easily violate global constraints. (f) Consistent query answering in non-relational database, e.g. XML, RDF. (g) Consistent exchange of data between peers, etc.