Dynamic data integration using Web services

We address the problem of large-scale data integration, where the data sources are unknown at design time, are from autonomous organisations, and may evolve. Experiments are described involving a demonstrator system in the field of health services data integration within the UK. Current Web services technology has been used extensively and largely successfully in these distributed prototype systems. The work shows that Web services provide a good infrastructure layer, but integration demands a higher level "broker" architectural layer; the paper identifies eight specific requirements for such an architecture that have emerged from the experiments, derived from an analysis of shortcomings which are collectively due to the static nature of the initial prototype. The way in which these are being met in the current version in order to achieve a more dynamic integration is described.