The Role of Structural Summaries for XML Retrieval.
Mirella Moura Moro, Zografoula Vagena · Brazilian Symposium on Databases · 2007
A Structural Summary of an XML document is a dynamically generated and maintained graph structure that preserves the structural characteristics of the document in a compact form. The versatility of structural summaries has been established with their extensive usage for diverse retrieval tasks. Within traditional XML query processing those structures have been used as primary indexes on the structure, as well as for (a) structure discovery, (b) query formulation, rewrite and optimization, (c) storage of statistics, and other important metadata information. At the same time, structural summaries have appeared within other XML retrieval scenarios including (a) XML keyword search, (b) information discovery within P2P systems, and (c) message routing within publish/subscribe systems. This tutorial introduces the concept of XML Structural Summaries and describes their role within XML retrieval. It covers the usage of those summaries for Database-style query processing, as well as Information Retrieval-style search tasks in the context of both centralized and distributed environments. Finally, it concludes with a presentation of new retrieval scenarios that can potentially be favorably supported by those summaries.