This paper concerns an expansion of first-order Belnap-Dunn logic, named $\mathrm{BD}^{\supset,\mathsf{F}}$, and an application of this logic in the area of relational database theory. The notion of a relational database, the notion of a query applicable to a relational database, and several notions of an answer to a query with respect to a relational database are considered from the perspective of this logic, taking into account that a database may be an inconsistent database or a database with null values. The chosen perspective enables among other things the definition of a notion of a consistent answer to a query with respect to a possibly inconsistent database without resort to database repairs. For each of the notions of an answer considered, being an answer to a query with respect to a database of the kind considered is decidable.

翻译：本文涉及扩大Belnap-Dunn第一阶逻辑,名为$\mathrm{BD<unk> supset,\ mathsf{F<unk> $,以及这一逻辑在关系数据库理论领域的应用。关系数据库的概念、适用于关系数据库的查询概念和对关系数据库查询的答案的若干概念是从这一逻辑角度考虑的,同时考虑到数据库可能是一个不一致的数据库或具有无效值的数据库。除其他外,所选择的观点使得对关于可能不一致的数据库的查询作出一致答复的概念得以定义,而不必使用数据库的修理。对于所考虑的回答的每一种概念,对于所考虑的关于关系数据库的查询的答案是可以消化的。</s>