Reuse the Deleted Labels for Vector Order-Based Dynamic XML Labeling Schemes

Abstract

Documents obeying XML standard are intrinsically ordered and typically modeled as a tree. Labeling schemes encode both document order and structural information so that queries can exploit them without accessing the original XML file. When XML data become dynamic, it is important to design labeling schemes that can efficiently facilitate updates as well as processing XML queries. Recently, vector order-based labeling schemes have been proposed to efficiently process updates in dynamic XML data. However the updates are focused on how to process the labels when a node is inserted into the XML; how to process the deleted labels is not considered in the previous researches. In this paper, we propose new algorithms to generate the labels with smallest size and therefore reuse all the deleted labels to control the label size increasing speed; meanwhile the algorithms can completely avoid the re-labeling also. Extensive experimental results show that the algorithms proposed in this paper can control the label size increasing speed and enhance the query performance.