ActiveXQBE: A Visual Paradigm for Triggers over XML Data

Abstract

Abstract. While XQuery is becoming a standard, the W3C is currently discussing the features of an update language for XML, and its requirements. Therefore, time is ripe for designing and defining the language features and extensions that are usually needed when updates are supported: reaction policies to constraint violations, business rules, and more. In the past years, several languages have been proposed for updates as well as for triggers in XML, such as XUpdate and Active XQuery.In this paper, we propose a visual approach to the formulation of active rules building on XQBE, a graphical query language for XML data. Our approach is motivated by the need to provide unskilled users with the ability to express business rules in an intuitive fashion. Visual triggers are then translated into statements that can be interpreted by query engines.