XPath: Looking Forward

Olteanu, Dan; Meuss, Holger; Furche, Tim; Bry, François

doi:10.1007/3-540-36128-6_7

Cited by 139 publications

(137 citation statements)

References 7 publications

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“…they subsume each other) -q 1 strictly subsumes q 2 The first case is the easier one. If q 1 and q 2 are subsumption equivalent, then there is no tree t, such that t simulates with one, but not the other.…”

Section: Completeness Theorem 1 (Subsumption By Transformationmentioning

confidence: 99%

“…Like most approaches to Web data (or semi-structured data, in general), they are distinguished from relational query languages such as SQL by a set of query constructs specifically attuned to the less rigid, often diverse, or even entirely schema-less nature of Web data. Xcerpt terms are similar to normalized forward XPath (see [2]) but extended with variables, deep-equal, a notion of injective match, regular expressions, and full negation. Thus, they achieve much of the expressiveness of XQuery without sacrificing the simplicity and pattern-structure of XPath.…”

Section: Introductionmentioning

confidence: 99%

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Simulation Subsumption or Déjà vu on the Web

Bry¹,

Furche²,

Linse³

2008

Web Reasoning and Rule Systems

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Abstract. Simulation unification is a special kind of unification adapted to retrieving semi-structured data on the Web. This article introduces simulation subsumption, or containment, that is, query subsumption under simulation unification. Simulation subsumption is crucial in general for query optimization, in particular for optimizing pattern-based search engines, and for the termination of recursive rule-based web languages such as the XML and RDF query language Xcerpt. This paper first motivates and formalizes simulation subsumption. Then, it establishes decidability of simulation subsumption for advanced query patterns featuring descendant constructs, regular expressions, negative subterms (or subterm exclusions), and multiple variable occurrences. Finally, we show that subsumption between two query terms can be decided in O(n! n ) where n is the sum of the sizes of both query terms.

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Section: Completeness Theorem 1 (Subsumption By Transformationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Simulation Subsumption or Déjà vu on the Web

Bry¹,

Furche²,

Linse³

2008

Web Reasoning and Rule Systems

Self Cite

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“…Recently an XQuery implementation [7] and some XPath implementations [20,9,16,23] that operate over XML streams have been reported. In [7], Florescu et al describe a XQuery engine designed for data transformations on XML streams based on the iterator model.…”

Section: Related Workmentioning

confidence: 99%

“…While the focus of this engine is on completenes, TurboXPath, on the other hand, has been designed as high-performance iterator that can be used by an iterator-based query processor. The XPath processors proposed in [16,20,23] are based on connecting a set of FA in a network that represents the query. These approaches support a much smaller set of features compared to TurboXPath and may require memory that grows exponentially with the size of the query.…”

Section: Related Workmentioning

confidence: 99%

An evaluation of binary xml encoding optimizations for fast stream based xml processing

Bayardo

Gruhl

Josifovski

et al. 2004

Proceedings of the 13th International Conference on World Wide Web

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This paper provides an objective evaluation of the performance impacts of binary XML encodings, using a fast stream-based XQuery processor as our representative application. Instead of proposing one binary format and comparing it against standard XML parsers, we investigate the individual effects of several binary encoding techniques that are shared by many proposals. Our goal is to provide a deeper understanding of the performance impacts of binary XML encodings in order to clarify the ongoing and often contentious debate over their merits, particularly in the domain of high performance XML stream processing.

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“…Query-construct requests involving a complex data retrieval might be confusing, 2. unnecessarily complex path selections, e.g. XPath expressions involving both forward and reverse axes, are possible [8], 3. in case of several path selections, the overall structure of the retrieved data items might be difficult to grasp, as in Example 1.…”

Section: Introductionmentioning

confidence: 99%

The XML Query Language Xcerpt: Design Principles, Examples, and Semantics

Bry¹,

Schaffert²

2003

Web, Web-Services, and Database Systems

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Abstract. Most query and transformation languages developed since the mid 90es for XML and semistructured data -e.g. XQuery [1], the precursors of XQuery [2], and XSLT [3] -build upon a path-oriented node selection: A node in a data item is specified in terms of a root-to-node path in the manner of the file selection languages of operating systems. Constructs inspired from the regular expression constructs * , +, ?, and "wildcards" give rise to a flexible node retrieval from incompletely specified data items. This paper further introduces into Xcerpt, a query and transformation language further developing an alternative approach to querying XML and semistructured data first introduced with the language UnQL [4]. A metaphor for this approach views queries as patterns, answers as data items matching the queries. Formally, an answer to a query is defined as a simulation [5] of an instance of the query in a data item.

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XPath: Looking Forward

Cited by 139 publications

References 7 publications

Simulation Subsumption or Déjà vu on the Web

Simulation Subsumption or Déjà vu on the Web

An evaluation of binary xml encoding optimizations for fast stream based xml processing

The XML Query Language Xcerpt: Design Principles, Examples, and Semantics

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