Holistic Twig Joins: Optimal XML Pattern Matching Written by: Nicolas Bruno Nick Koudas Divesh Srivastava Presented by: Jose Luna John Bassett

What is XML? Extensible Markup Language Tag-based markup language that allows you to share structured information Information is easily transferred across systems

XML Example

Twigs A twig is simply a subtree Example (ignore numbers for now):

What is XQuery? Query language designed to query collections of XML data XQuery is a full-fledged query language, but we are only concerned with ancestor- descendent and parent-child relationships.

XQuery Relationships Single line indicates parent-child relationship Double line indicates an ancestor- descendent relationship

XQuery Example 1 Query: book[title = ‘XML’ and year = ‘2000’] Associated query tree:

XQuery Example 2 Query: book[title = ‘XML’]//author[fn = ‘jane’ AND ln = ‘doe’] Associated query tree:

XB-Trees An XB-Tree is simply a B-Tree that is designed to index this XML data using the positional data Indexing using (LeftPos : RightPos) Querying is done just as is done in a regular B-Tree

XB-Tree Example

Experimental Results

Questions? Thank you!