Exchanging intensional XML data

Abstract

XML is becoming the universal format for data exchange between applications. Recently, the emergence of Web services as standard means of publishing and accessing data on the Web introduced a new class of XML documents, which we call intensional documents. These are XML documents where some of the data is given explicitly while other parts are defined only intensionally by means of embedded calls to Web services.When such documents are exchanged between applications, one has the choice to materialize the intensional data (i.e. to invoke the embedded calls) or not, before the document is sent. This choice may be influenced by various parameters, such as performance and security considerations. This paper addresses the problem of guiding this materialization process.We argue that, just like for regular XML data, schemas (ala DTD and XML Schema) may be used to control the exchange of intensional data and, in particular, to determine which data should be materialized before sending a document, and which should not. We formalize the problem and provide algorithms to solve it. We also present an implementation that complies with real life standards for XML data, schemas, and Web services, and is used in the Active XML system [3,1]. * This project is partially supported by EU IST project DBGlobe

Hedge-Based Filtering Method for Semi-structure Documents

“…However, the ability of this method is limited, which doesn't support "[]", nor DTD mode. Reference [14] constrained query sentence using XML schema mode, but the method is mainly used for intentional data in the web services. Reference [15] completed the simplify rewrite of the XPath expressions using of DTD, rewritten Xpath by the use of equivalent rules, and proved that the algorithm is perfect on a specific DTD and XPath.…”

Efficient execution of composite Web services exchanging intensional data

“…Milo et al [24] provided document and schema rewriting methods to support the exchange of intensional data between heterogeneous applications. Ruberg et al [32] proposed an approach to materializing service calls in an AXML document stored in a node in a peer-to-peer environment.…”

“…Moreover, dynamic type validation should be performed on the input and output messages of the Web services. In [24], an extended version of XML schema and WSDL was proposed to support the use of intensional data in the description of Web services and a schema enforcement method was also presented for verifying and rewriting intensional parameters and results. These techniques can be utilized to implement our approach.…”

Lazy query evaluation for Active XML

“…A recent work [21] addressed the issue of call invocations for exchanging AXML documents. There, the goal was to identify the calls that need to be invoked for making a document match an XML schema, and the solution relied on schema analysis via automata-based algorithms.…”

“…By contrast, our goal here is to find the sequence of call invocations needed to evaluate a query over AXML data, and the solution is based on query analysis and rewriting. Indeed the two techniques are complementary: The techniques of [21] can be used to ensure that the parameters of calls invoked in our query processing match the type required by the service signature, and can also be applied to query results if they need to be exchanged. Conversely, our technique can be used to evaluate queries on exchanged AXML data.…”