XQuery at your web service

Abstract

XML messaging is at the heart of Web services, providing the flexibility required for their deployment, composition, and maintenance. Yet, current approaches to Web services development hide the messaging layer behind Java or C# APIs, preventing the application to get direct access to the underlying XML information. To address this problem, we advocate the use of a native XML language, namely XQuery, as an integral part of the Web services development infrastructure. The main contribution of the paper is a binding between WSDL, the Web Services Description Language, and XQuery. The approach enables the use of XQuery for both Web services deployment and composition. We present a simple command-line tool that can be used to automatically deploy a Web service from a given XQuery module, and extend the XQuery language itself with a statement for accessing one or more Web services. The binding provides tight-coupling between WSDL and XQuery, yielding additional benefits, notably: the ability to use WSDL as an interface language for XQuery, and the ability to perform static typing on XQuery programs that include Web service calls. Last but not least, the proposal requires only minimal changes to the existing infrastructure. We report on our experience implementing this approach in the Galax XQuery processor.

Efficient Distribution of Full-Fledged XQuery

“…The variable $t becomes the parameter of the generated function containing the second for-loop (see also Table IV); (iii) under the pass-by-projection semantics, the query is decomposed in the same way as using pass-by-fragment, however, when serializing the request messages, a projection of $t/attribute::id (parameter projection) and $c/child::annotation/child:author (result projection) is calculated. The test set thus contains four queries in total, and each of them is executed on 2 documents of sizes 10,20,40,80 and 160MB.…”

“…In this respect, XRPC differs with its focus on interoperability, as it acts as a pure XQUERY rewriter (not making any assumptions on the system internals of the participating peers). Galax Yoo-Hoo [20] accesses web services using SOAP RPC as the communication protocol, which lacks proper support for XML elements and sequences; a problem addressed by XRPC using a specific literal SOAP message encoding. Active XML (AXML) [1], [2] is a declarative framework that harnesses web services for data integration in a peer-to-peer architecture.…”

StreetTiVo: Using a P2P XML Database System to Manage Multimedia Data in Your Living Room

“…The recent W3C Candidate Recommendation XQuery Update Facility (XQUF) [22] introduces a built-in function fn:put() for remote storage of XML documents, which again implies data shipping. There have been various proposals to equip XQuery with function shipping style distributed querying abilities [23,24,25]. On the syntax level, we consider our XRPC proposal an incremental development of these.…”

Ontology Driven Data Mediation in Web Services

“…In this work, we use a popular representation for mappings in Web services, XQuery and XSLT , (Onose, 2004) and use SAWSDL to associate these mappings with Web service elements. We believe that most of the mappings that are required to resolve heterogeneities between Web service elements can be concisely represented using XQuery or XSLT.…”