Effective Structural Joins using Level Information
Jongik Kim · 2008
Structural join is one of the most typical techniques for evaluating XML path queries. Recent researches for structural joins focus on techniques of skipping unnecessary elements using the horizontal distribution information of elements that is indexed on a structure like B+ tree. However, those techniques make the structural join complicated and cannot guarantee efficient join processing due to the overhead of an index structure. In this paper, we propose a new structural join technique that exploits the level information of XML elements. Our technique can skip unnecessary elements using level information, which is vertical distribution information of elements. Through the experimental results, we show that our technique can evaluate structural joins efficiently.