An efficient encoding and labeling for dynamic XML data

In order to efficiently determine structural relationships among XML elements and to avoid re-labeling for updates, much research about labeling schemes has been conducted, recently. However, a harmonic support of efficient query processing and updating has not been achieved. In this paper, we propose an efficient XML encoding and labeling scheme, called EXEL, which is a variant of the region numbering scheme using bit strings. In order to generate the ordinal and insert-friendly bit strings in EXEL, a novel binary encoding method is devised. Also, we devise a labeling scheme for a newly inserted node which incurs no re-labeling of pre-existing labels. These encoding and inserting methods are the bases of efficient query processing and the complete avoidance of re-labeling for updates. Moreover, EXEL supports all structural relationships in XPath and the relationships can be checked by SQL statements supported by an RDBMS. Finally, the experimental results show that EXEL provides fairly reasonable query processing performance while completely avoiding re-labeling for updates.