A Persistent Labeling Scheme for Dynamic Ordered XML Trees

Abstract

XML is becoming the new standard for the exchange and publishing of data over the Internet. Documents obeying the XML standard can be viewed as trees basically the parse tree of the document. XML database systems often give each item in the document (node in the tree) a unique logical identifier (called a label) and use those labels for an efficient processing of queries, in particular queries involving structural conditions or testing for changes in the document content. Therefore several path indexing and numbering schemes have been proposed. XML data on the Web are subjected to frequent updates. During the update on XML data, most of these approaches will need to recompute existing labels, which is rather time consuming. The goal of our labeling scheme is to design a persistent structural labeling scheme that supports the representation of ancestor-descendant relationship and sibling relationship between nodes. Moreover our labeling scheme supports insertion of new nodes at arbitrary positions in the XML tree without re-labeling and without conflicting existing labels.