Compacting XML Structures Using a Dynamic Labeling Scheme

Abstract

Due to the growing popularity of XML as a data exchange and storage format, the need to develop efficient techniques for stor- ing and querying XML documents has emerged. A common approach to achieve this is to use labeling techniques. However, their main prob- lem is that they either do not support updating XML data dynamically or impose huge storage requirements. On the other hand, with the ver- bosity and redundancy problem of XML, which can lead to increased cost for processing XML documents, compaction of XML documents has be- come an increasingly important research issue. In this paper, we propose an approach called CXDLS combining the strengths of both, labeling and compaction techniques. Our approach exploits repetitive consecu- tive subtrees and tags for compacting the structure of XML documents by taking advantage of the ORDPATH labeling scheme. In addition it stores the compacted structure and the data values separately. Using our proposed approach, it is possible to support efficient query and update processing on compacted XML documents and to reduce storage space dramatically. Results of a comprehensive performance study are provided to show the advantages of CXDLS.