Assertion Support for Manipulating Constrained Data-Centric XML

XML is used for different purposes. They are interested in data-centric applications of XML where it is used to handle structured data in loosely coupled, distributed systems. In many such scenarios, it is important that the XML data complies to structural and integrity constraints, in particular to value-based constraints. This paper presents a technique to maintain the invariants. For a core procedural manipulation language, they show how to automatically derive the weakest precondition of procedures for the constraints. They present a formalization of a data-centric XML abstraction and an assertion language that enables weakest precondition generation. The framework allows to automatically simplify and reduce the generated preconditions such that checking becomes independent of the size of the constraint definitions.