XPath satisfiability in the presence of DTDs
نویسندگان
چکیده
منابع مشابه
XPath Query Satisfiability is in PTIME for Real-World DTDs
The problem of XPath query satisfiability under DTDs (Document Type Definitions) is to decide, given an XPath query p and a DTD D, whether or not there is some document valid with respect to D on which p returns a nonempty result. Recent studies in the literature have shown the problem to be NP-hard or worse for most fragments of XPath. However, in this paper we show that the satisfiability pro...
متن کاملSatisfiability of Simple XPath Fragments under Duplicate-Free DTDs
In this paper, we consider the XPath satisfiability problem under restricted DTDs called “duplicate free”. For an XPath expression q and a DTD D, q is satisfiable under D if there exists an XML document t such that t is valid against D and that the answer of q on t is nonempty. Evaluating an unsatisfiable XPath expression is meaningless, since such an expression can always be replaced by an emp...
متن کاملSatisfiability of Simple XPath Fragments under Fixed DTDs
The XPath satisfiability problem is to decide, for an XPath expression q and a DTD D, if there exists an XML document t valid against D such that the answer of q on t is nonempty. It is shown that the satisfiability problem is intractable for many XPath fragments. In this paper, we focus on fixed DTDs and consider the problem under fixed DTDs. We first show that, for a very restricted XPath fra...
متن کاملXPath Containment in the Presence of Disjunction, DTDs, and Variables
XPath is a simple language for navigating an XML tree and returning a set of answer nodes. The focus in this paper is on the complexity of the containment problem for various fragments of XPath. In addition to the basic operations (child, descendant, filter, and wildcard), we consider disjunction, DTDs and variables. W.r.t. variables we study two semantics: (1) the value of variables is given b...
متن کاملValidity of Positive XPath Queries with Wildcard in the Presence of DTDs
This paper discusses the validity problem for positive XPath queries with wildcard in the presence of DTDs. A given XPath query p is valid under a DTD D if, for every XML document T conforming to D, the answer to p on T is nonempty. The validity problem is one of the basic static analyses of queries, together with the satisfiability and the containment problems. Although the validity problem is...
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ژورنال
عنوان ژورنال: Journal of the ACM
سال: 2008
ISSN: 0004-5411,1557-735X
DOI: 10.1145/1346330.1346333