Conjunctive-Query Containment and Constraint Satisfaction
نویسندگان
چکیده
منابع مشابه
Conjunctive Query Containment Revisited
We consider the problems of conjunctive query containment and minimization, which are known to be NP-complete, and show that these problems can be solved in polynomial time for the class of acyclic queries. We then generalize the notion of acyclicity and deene a parameter called query width that captures the \degree of cyclicity" of a query: in particular, a query is acyclic if and only if its ...
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The complexity of containment and satisfiability of conjunctive queries over finite, unranked, labeled trees is studied with respect to the axes Child , NextSibling , their transitive and reflexive closures, and Following . For the containment problem a trichotomy is presented, classifying the problems as in PTIME, coNP-complete, or Π 2 -complete. For the satisfiability problem most problems ar...
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The management of semistructured data has recently received signiicant attention because of the need of several applications to model and query large volumes of irregular data. This paper considers the problem of query containment for a query language over semistructured data, StruQL0, that contains the essential feature common to all such languages, namely the ability to specify regular path e...
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A constraint satisfaction problem may not admit a complete solution; in this case a good partial solution may be acceptable. This paper presents new techniques for organizing search with branch and bound algorithms so that maximal partial solutions (those having the maximum possible number of satisfied constraints) can be obtained in reasonable time for moderately sized problems. The key featur...
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ژورنال
عنوان ژورنال: Journal of Computer and System Sciences
سال: 2000
ISSN: 0022-0000
DOI: 10.1006/jcss.2000.1713