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XML Example
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Holistic Twig Joins:Optimal XML Pattern Matching
Written by:Nicolas BrunoNick 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’]
• Associatedquery 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
Experimental Results
Experimental Results
Experimental Results
Experimental Results
Experimental Results
Questions?
Thank you!