1. Querying Large XML Data Hsuan-Heng, Wu Shawn Ju

2. XML V.S. HTML XML is designed to describe data XML don’t use predefined tags XML is used to exchange data between applications Tree Structure but allow Reference to other node Tags v.s. Attributes

3. XML Query : Path and Twig PATH PATTERN A/B DIRCECT DESCENDENT A//B DESCENDENT TWIG PATTERN A[@attr = “??”]/B A[@attr = “??”] // B “/publisher//title” return all title elements under all top- level publisher elements “/publisher[@name=MITPress]/book/title” returns all book titles of the publisher with name “MIT Press.”

4. Run an Example ○ /book//author ○/book//author [@id = 6]

5. Run an Example : Relational Approach Book ( Integer Pre, Integer Post, Value v1, Value v2 …) ; Author ( Integer Pre, Integer Post, Value v1, Value v2...) ; Select A.value from Author A, Book B where B.pre < A. pre and A.post < B.post ; Select A.value from Author A, Book B where B.pre < A.pre and A.post < B.post and B.name =’Ted’ ; (2,5) ( 1,20 ) (3,4) (6,9) (7,8)(11,12)(13,14) (10,15) (17,18) (16,19) 9

6. Run an Example : Index Graph Approach 9