XQuery on SQL Hosts

Grust, Torsten; SAKR, S; Teubner, Jens

doi:10.1016/b978-012088469-8/50025-5

Cited by 35 publications

(57 citation statements)

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“…Further details of Relational XQuery do not affect our present discussion of distributivity or IFP evaluation and may be found in [15]. In the following, let e denote the algebraic plan that has been compiled for XQuery expression e. …”

Section: Distributivity and Relational Xquerymentioning

confidence: 99%

“…Pathfinder compiles instances of the XQuery Data Model (XDM) and XQuery expressions into relational tables and algebraic plans over these tables, respectively, and thus follows the dashed path in Figure 6. The translation strategy built into the compiler has been carefully designed (i) to faithfully preserve the XQuery semantics (including compositionality, node identity, iteration and sequence order), and (ii) yield relational plans which exclusively rely on regular relational query engine technology (no specific operators or index structures are required, in particular) [15]. The compiler emits a dialect of relational algebra that mimics the capabilities of modern SQL query engines (Table 1).…”

Section: Distributivity and Relational Xquerymentioning

confidence: 99%

“…Beyond recursion, this may lead to improved XQuery compilation strategies for back-ends that can exploit such independence, e.g, setoriented relational query processors (cf. loop-lifting [15]) as well as parallel or distributed execution platforms.…”

Section: Wrap-upmentioning

confidence: 99%

“…Distributivity may be assessed on a syntactical level-a non-invasive approach that can easily be realized on top of existing XQuery processors (Section 3). Further, though, if we adopt a relational view of the XQuery semantics (as in [15]), the seemingly XQuery-specific distributivity notion turns out to be elegantly and uniformly tractable on the familiar algebraic level (Section 4).…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

An Inflationary Fixed Point Operator in XQuery

Afanasiev

Grust²,

Marx

et al. 2008

2008 IEEE 24th International Conference on Data Engineering

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Section: Distributivity and Relational Xquerymentioning

confidence: 99%

Section: Distributivity and Relational Xquerymentioning

confidence: 99%

Section: Wrap-upmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

An Inflationary Fixed Point Operator in XQuery

Afanasiev

Grust²,

Marx

et al. 2008

2008 IEEE 24th International Conference on Data Engineering

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“…To pinpoint the impact of such fine-grained cardinality forecasts, we used the Pathfinder relational XQuery compiler [11] to generate a SQL formulation of the XQuery expression doc("forecast· · · ")/descendant::day/descendant::ppcp…”

Section: Introductionmentioning

confidence: 99%

Dependable cardinality forecasts for XQuery

Teubner

Grust²,

Maneth

et al. 2008

Proc. VLDB Endow.

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Though inevitable for effective cost-based query rewriting, the derivation of meaningful cardinality estimates has remained a notoriously hard problem in the context of XQuery. By basing the estimation on a relational representation of the XQuery syntax, we show how existing cardinality estimation techniques for XPath and proven relational estimation machinery can play together to yield dependable forecasts for arbitrary XQuery (sub)expressions. Our approach benefits from a light-weight form of data flow analysis. Abstract domain identifiers guide our query analyzer through the estimation process and allow for informed decisions even in case of deeply nested XQuery expressions. A variant of projection paths [15] provides a versatile interface into which existing techniques for XPath cardinality estimation can be plugged in seamlessly. We demonstrate an implementation of this interface based on data guides. Experiments show how our approach can equally cope with both, structureand value-based queries. It is robust with respect to intermediate estimation errors, from which we typically found our implementation to recover gracefully.

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TIJAH at INEX 2004 Modeling Phrases and Relevance Feedback

Mihajlović

Ramirez²,

Vries³

et al. 2005

Advances in XML Information Retrieval

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Abstract. This paper discusses our participation in INEX using the TIJAH XML-IR system. We have enriched the TIJAH system, which follows a standard layered database architecture, with several new features. An extensible conceptual level processing unit has been added to the system. The algebra on the logical level and the implementation on the physical level have been extended to support phrase search and structural relevance feedback. The conceptual processing unit is capable of rewriting NEXI content-only and content-and-structure queries into the internal form, based on the retrieval model parameter specification, that is either predefined or based on relevance feedback. Relevance feedback parameters are produced based on the data fusion of result element score values and sizes, and relevance assessments. The introduction of new operators supporting phrase search in score region algebra on the logical level is discussed in the paper, as well as their implementation on the physical level using the pre-post numbering scheme. The framework for structural relevance feedback is also explained in the paper. We conclude with a preliminary analysis of the system performance based on INEX 2004 runs.

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XQuery on SQL Hosts

Cited by 35 publications

References 0 publications

An Inflationary Fixed Point Operator in XQuery

An Inflationary Fixed Point Operator in XQuery

Dependable cardinality forecasts for XQuery

TIJAH at INEX 2004 Modeling Phrases and Relevance Feedback

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