Exception handling for XML query execution plans in a Web service environment

Assembling information for queries from distributed heterogeneous resources is a challenging and important process for inter-organizational collaboration and service provision. However, traditional distributed databases approaches ignore human intervention and most exception handling in the process. Therefore, we propose a work-flow-based approach to address this problem. This is particularly suitable in a loosely coupled and autonomous Web services environment, in which XML query plans are formulated in XQuery. We demonstrate the feasibility of our approach with a healthcare data integration case study and examine some typical use cases of exceptions handling in XQuery.