PathStack¬: A Holistic Path Join Algorithm for Path Query with Not-Predicates on XML Data

Abstract

Abstract. The evaluation of path queries forms the basis of complex XML query processing which has attracted a lot of research attention. However, none of these works have examined the processing of more complex queries that contain not-predicates. In this paper, we present the first study on evaluating path queries with not-predicates. We propose an efficient holistic path join algorithm, PathStack ¬ , which has the following advantages: (1) it requires only one scan of the relevant data to evaluate path queries with not-predicates; (2) it does not generate any intermediate results; and (3) its memory space requirement is bounded by the longest path in the input XML document. We also present an improved variant of PathStack ¬ that further minimizes unnecessary computations.

Extending path summary and region encoding for efficient structural query processing in native XML databases

“…On the other hand, Jiang et al (2004) also propose to process twig queries with other relational operators other than joins, i.e., an OR predicate. This motivated Jiao et al (2005) and Yu et al (2006) to investigate other relational operators, such as NOT predicates, and their outcomes on some holistic join algorithms for path and twig query respectively.…”

Holistically Stream-based Processing Xtwig Queries

“…First, we propose a new stack structure called Stick Stack to store the temporary answers caused by the sticks, then propose a stream-based algorithm called BCube to process the matching of vpatterns with vtwig based on the new proposed stick stack structure. b1 [4,19] d1 [5,12] d3 [13,18] f1 [7,8] f2 [9,10]f4 [15,16] f3 [14,17] …”

“…There are lots of works that evaluate queries with only forward axes, such as path pattern [3,25] and twig pattern [19]. With the rewriting rules, Q 1 can be transformed into a twig query which can be evaluated using existing algorithms such as PathStack [13], TwigStack [5], TJFast [14], PPS [9], Extended Dewey [15], CCPI [22] or Twig2Stack [8]. But the transformed query patterns contain equality joins of nodes, and remain expensive to evaluate.…”

Holistic Join for Generalized Tree Patterns

“…Jiao et al [16] presented an algorithm for finding the matches for a path query (unlike a twig, it has no branches) containing not , in a document. There seems to be no natural way to extend HTJ to twigs containing not.…”