Preference XPATH: A Query Language for E-Commerce

We present a new XML-based search technology for e-commerce that enables users to formulate complex customer or vendor preferences, which typically occur within B2C or B2B applications. Preferences are modeled in a very natural way by partial orders. Since our semantics of multi-attribute preferences implements the Pareto-optimality principle, Preference XPATH queries avoid both the unwanted "empty-result"-effect and the flooding-effect with lots of irrelevant query results. If perfect matches are not available bestpossible alternatives are found instead. We have extended the XML query language XPATH by the capability to formulate preferences as soft selection conditions. As our syntax extensions are fully compatible with the XPATH standard, both hard and soft selection conditions become now available to any XML-based e-commerce application. Several e-shopping examples show how easy and elegant it is to transform customer wishes into Preference XPATH queries. Sample query evaluations demonstrate that query results are intuitively comprehensible. Our prototype implementation is smoothly integrated with the commercial XML database system Tamino of Software AG. Moreover, we show how Preference XPATH can be used within the popular XML query language QUILT. It even merges with XML style sheets (XSLT). Thus with Preference XPATH powerful personalized search engines, match-making processes, or content syndications for B2C and B2B applications can be implemented completely inside the XML framework.