The XML Query Execution Engine (XEE)

Abstract

The characteristics of XML documents require new ways of storing and querying such documents. Queries on both textual content and structural aspects must be supported efficiently. In this paper, we introduce the motivation and concept of our XML Query Execution Engine (XEE) and its current implementation. XEE provides a testbed for our Access Support Tree and TextArray data structure of which the basic idea is to separate the (logical) structure of a document from its "visible" text content. Based on this concept, we bring together database and information retrieval technology to improve storage, retrieval, and querying of large XML document collections, in particular with respect to updates. We motivate our approach and present criteria that influence our system design. Furthermore, we introduce the XEE system architecture and give insight into the concept of XEE components. Especially, we explain our current approach of efficiently implementing Access Support Trees for secondary storage and reveal issues that arise when implementing such a system.