Matching of Twig Pattern with AND/OR Predicates over XML Streams

Chapter 5 presents a novel approach for processing complex twig pattern with OR-predicates and AND-predicates over XML document streams which a twig pattern is represented as a query tree. Its OR-predicates and AND-predicates are represented as a separate abstract syntax tree associated with the branch node, and all the twig patterns are combined into a single prefix query tree that represents such queries by sharing their common prefixes. Consequently, all the twig patterns are evaluated in a single, document-order pass over the input document stream avoiding the translation of the set of twig patterns into a finite state automaton. Chapter 1 introduces the background of this issue. Chapter 2 discusses the representation of complex twig pattern as a query tree, how to combine a set of twig patterns into a single query three, how to match multi twig patterns over the incoming XML document, and possible optimization of computing logical AND/OR predicates. In section 3, the architecture of a XML stream process system named LeoXSQ is given. Section 4 shows the conducted experiments. In section 5, the related work is discussed. Section 6 summarizes this chapter.