1. MIX: A Meta-Data Indexing System for XML SungRan Cho, L3S Nick Koudas, University of Toronto Divesh Srivastava, AT&T Labs-Research

2. Motivation Diverse information over the Web - quality (e.g., accuracy, recency), security Queryable for meta-data with underlying data  Annotate XML data with a variety of meta-data  Efficiently identify data that meet desired constraints on meta-data

3. Our Meta-data Model Meta-data levels - Assigned to elements by associating an attribute One-sided range constraint - find all sales with approximation error < 5% - update timestamp > 2005-Jan-01 - find senate documents with security level < `secret` Inheritance - A meta-data level is automatically inherited by its sub- elements unless explicitly specified

4. MDI (Meta-data Indexes) Develop a family of Meta-data Indexes - Multi-dimensional index structure Features of Meta-data Indexes - Actual meta-data levels - Inherited meta-data levels - Inheritance source nodes

5. MIX (Meta-data Indexing for XML) Meta-data indexed querying - Support for all XPath axes Dynamic maintenance of meta-data - Add, delete, change

6. Architecture of MIX MDI Management Meta-data Specification Bulk Load Index Maintenance MDI XML Stores XPath Querying Query Result Meta-data threshold Execution Engine Meta-data change

7. Thank you