In this paper, we study consistent query answering in tables with nulls and functional dependencies. Given such a table T, we consider the set Tuples of all tuples that can be built up from constants appearing in T, and we use set theoretic semantics for tuples and functional dependencies to characterize the tuples of Tuples in two orthogonal ways: first as true or false tuples, and then as consistent or inconsistent tuples. Queries are issued against T and evaluated in Tuples. In this setting, we consider a query Q: select X from T where Condition over T and define its consistent answer to be the set of tuples x in Tuples such that: x is a true and consistent tuple with schema X and there exists a true super-tuple t of x in Tuples satisfying the condition. We show that, depending on the status that the super-tuple t has in Tuples, there are different types of consistent answer to Q. The main contributions of the paper are: (a) a novel approach to consistent query answering not using table repairs; (b) polynomial algorithms for computing the sets of true-false tuples and the sets of consistent-inconsistent tuples of Tuples; (c) polynomial algorithms in the size of T for computing different types of consistent answer for both conjunctive and disjunctive queries; and (d) a detailed discussion of the differences between our approach and the approaches using table repairs.

翻译：在本文中, 我们用空格和功能依赖性的表格来研究一致的问答。 在这样的表格 T 中, 我们考虑从 T 中的常数中可以建立的所有图例的设置图例, 我们用图例和功能依赖性来设置词义性词义性词义, 以两种正统方式描述图例图例的图例: 首先作为真实的或假的图例, 然后作为一致或不一致的图例。 Queries 针对 T 发布, 并在图例中进行评估 。 在此设置中, 我们考虑一个查询 Q: 从 T 中选择 X, 在 T 的 Condition 上, 定义其一致的答案是图例 x 的设置 : x 是真实和一致的图例性词义性词义性词义性词义性词义性词义, 在图例中存在符合条件的 x 真正的超级图例 。 我们显示, 根据图例中的超级图例 和图例 的表格有不同的答案 。 本文的主要解 : (a) a lialtialtial ty ty ty tual tuction 和 tral comcaltic coal coal 。