Journal ArticleDOI
A sound and sometimes complete query evaluation algorithm for relational databases with null values
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A sound and, in certain cases, complete method is described for evaluating queries in relational databases with null values where these nulls represent existing but unknown individuals.Abstract:
A sound and, in certain cases, complete method is described for evaluating queries in relational databases with null values where these nulls represent existing but unknown individuals. The soundness and completeness results are proved relative to a formalization of such databases as suitable theories of first-order logic. Because the algorithm conforms to the relational algebra, it may easily be incorporated into existing relational systems.read more
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Logic and Databases: A Deductive Approach
TL;DR: It is shown that logic provides a convenient formalism for studying classical database problems and the representation and manipulation of deduced facts and incomplete information is shown.
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The management of probabilistic data
TL;DR: A data model that includes probabilities associated with the values of the attributes, and the notion of missing probabilities is introduced for partially specified probability distributions, offers a richer descriptive language allowing the database to more accurately reflect the uncertain real world.
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On the representation and querying of sets of possible worlds
TL;DR: This work provides matching upper and lower bounds on the data-complexity of testing containment, membership and uniqueness for sets of possible worlds and shows that the certain fact problem is coNP-complete, even for a fixed first order query applied to a Codd-table.
Proceedings ArticleDOI
On the representation and querying of sets of possible worlds
TL;DR: The approach is algebraic but the authors' bounds also apply to logical databases, and it is shown that the approach is, in a sense, the best possible, by deriving two NP-completeness lower bounds for the bounded possible fact problem when the fixed query contains either negation or recursion.
BookDOI
Managing and Mining Uncertain Data
TL;DR: Managing and Mining Uncertain Data, a survey with chapters by a variety of well known researchers in the datamining field, presents the most recent models, algorithms, and applications in the uncertain data mining field in a structured and concise way.
References
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Book
Symbolic Logic and Mechanical Theorem Proving
TL;DR: This book contains an introduction to symbolic logic and a thorough discussion of mechanical theorem proving its applications and how it can be applied to various areas such as question answering, problem solving, program analysis, and program synthesis.
Journal ArticleDOI
Extending the database relational model to capture more meaning
TL;DR: In this paper, the relational model is extended to support atomic and molecular semantics, which is a synthesis of many ideas from the published work in semantic modeling plus the introduction of new rules for insertion, update, and deletion.
Book ChapterDOI
On closed world data bases
TL;DR: This paper shows that closed world evaluation of an arbitrary query may be reduced to open world evaluated of so-called atomic queries, and shows that the closed world assumption can lead to inconsistencies, but for Horn data bases no such inconsistencies can arise.
Book ChapterDOI
Towards a Logical Reconstruction of Relational Database Theory
TL;DR: In this paper, the currency on loan is model theoretic in the sense that a database can be viewed as a particular kind of first order interpretation, and query evaluation is a process of truth functional evaluation of first-order formulae with respect, to this interpretation.
Proceedings ArticleDOI
Extending the data base relational model to capture more meaning
TL;DR: This paper proposes extensions to the relational model to support certain atomic and molecular semantics, and represents a synthesis of many ideas from the published work in semantic modeling.