On Distributing XML Repositories

XML is increasingly used not only for data exchange but also to represent arbitrary data sources as virtual XML repositories. In many application scenarios, fragments of such a repository are distributed over the Web. However, design and query models for distributed XML data have not yet been studied in detail. In this paper, we introduce a distribution approach for a virtual XML repository. We present a fragmentation method and outline an allocation model for distributed XML fragments. We also discuss an efficient realization based on small, local index structures. The index structures encode global path information and provide for an efficient, local evaluation of the most common types of global queries.