Abstract

Applications require access to multiple information sources and the data of other applications. WSDLbased web services are becoming a popular way of making information sources available on the web and, hence, to applications that need to consume them -- often via data integration systems that combine the data of multiple sources. We argue that the function signature paradigm that is used today by web services cannot capture the query capabilities provided by structurally rich and functionally powerful information sources, such as relational databases. We propose the Query Set Specification Language (QSSL) that allows the concise description of sets of parameterized XPath queries. A QSS is embedded in a WSDL specification to form a specialized type of web services, called Data Services. Data Services connect the calls that the source accepts with the underlying schema. QSSL will be enhanced to describe subsets of XQuery expressions beyond XPath ones.

Citations