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About yes/no queries against possibilistic databases
Author(s) -
Bosc Patrick,
Pivert Olivier
Publication year - 2007
Publication title -
international journal of intelligent systems
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.291
H-Index - 87
eISSN - 1098-111X
pISSN - 0884-8173
DOI - 10.1002/int.20224
Subject(s) - tuple , computer science , set (abstract data type) , relational database , probabilistic logic , database , possibility theory , relational calculus , algebraic number , conjunctive query , relational algebra , uncertain data , probabilistic database , theoretical computer science , data mining , information retrieval , relational model , database theory , mathematics , fuzzy set , fuzzy logic , artificial intelligence , discrete mathematics , programming language , mathematical analysis
This article is concerned with the handling of imprecise information in databases. The need for dealing with imprecise data is more and more acknowledged in order to cope with real data, even if commercial systems are most of the time unable to manage them. Here, the possibilistic setting is taken into consideration because it is less demanding than the probabilistic one. Then, any imprecise piece of information is modeled as a possibility distribution intended for constraining the more or less acceptable values. Such a possibilistic database has a natural interpretation in terms of a set of regular databases, which provides the basic gateway to interpret queries. However, if this approach is sound, it is not realistic, and it is necessary to consider restricted queries for which a calculus grounded on the possibilistic database, that is, where the operators work directly on possibilistic relations, is feasible. Extended yes/no queries are dealt with here, where their general form is: “to what extent is it possible and certain that tuple t (given) belongs to the answer to Q,” where Q is an algebraic relational query. A strategy for processing such queries efficiently is proposed under some assumptions as to the operators appearing in Q. © 2007 Wiley Periodicals, Inc. Int J Int Syst 22: 691–721, 2007.