1. Cooperative Query Answering for Semistructured data Michael Barg Raymond K. Wong Reviewed by SwethaJack Christian (Absent) Chris

2. Contents Introduction What is Cooperative Query Answering? Motivation Work Done Results with a detailed example Summary and related work

3. Introduction Semi structured data - XML Semi structured data - XML Self describing schema Self describing schema Heterogeneous data sources (combination of schemas) Heterogeneous data sources (combination of schemas) Standard XPATH query Standard XPATH query  REQUIRES ACCURATE UNDERSTANDING OF STRUCTURE

4. What is Cooperative Query Answering? Cooperative query answering (CQA) seeks to provide Cooperative query answering (CQA) seeks to provide relevant responses to queries posed by users in cases where a direct answer is not very helpful or informative. relevant responses to queries posed by users in cases where a direct answer is not very helpful or informative. Approximate or alternative information may be more useful and less misleading to a user. Approximate or alternative information may be more useful and less misleading to a user.Example: Q: “Is Sam an associate professor?” Q: “Is Sam an associate professor?” User believes most associate professors have tenure. User believes most associate professors have tenure. Sam is not tenured. Sam is an associate professor. Sam is not tenured. Sam is an associate professor. A: “Yes, but he doesn’t have tenure.” A: “Yes, but he doesn’t have tenure.”

5. Motivation To query XML Knowledge of underlying structure Knowledge of underlying structure Rich semantics come from structure Rich semantics come from structure Documents adhering to different schema located in same repository Documents adhering to different schema located in same repository

6. Work Done Edges -> relationships Nodes -> elements Algorithm is based on traversing the graph and scoring similarity.

7. Work Done (2) Algorithm: Cooperative Query Processing Input: Query Q, which is represented by the query tree, Q T Output: Set of ranked tuples, Output: Set of ranked tuples,

8. Result Desired Info Find all phone numbers of restaurants in Soho Actual Query //restaurant[//Soho]//phone number Results Phone numbers with an ancestor ”Restaurant” who had a child named ”Soho”, Phone numbers of restaurants with an address in Soho

9. Result (Cont’s)

11. Related Work Not well researched for semistructured data Well established in Relation Databases. Extending SQL Syntax Extending SQL Syntax Database (CoBase) Database (CoBase) Concept Similarities Concept Similarities Cooperative Interfacing Cooperative Interfacing

12. Summary Casual and non-expert users might not have accurate knowledge of the underlying structure. Cooperative Query Answering is a method which enables users to meaningfully query semi structured (i.e. XML) data. The paper suggested a graph based method to do this Traversing through the nodes Traversing through the nodes Results is promising Results is promising

13. Questions?

14. References M. Barg, R.K. Wong. Cooperative Query Answering for Semistructured Data. In Proceedings of the 14th Australasian Database Conference (ADC), Adelaide Australia, Feb 2003. S. Abiteboul. Querying semi-structured data. In Proceedings of the International Conference on Database Theory (ICDT). Springer Verlag, 1997. T. Bray, J. Paoli, and C.M. Sperberg-McQueen. Extensible markup language (XML)1.0. In W3C Recommendation, World Wide Web Consortium, 1998; available online at http://www.w3.org/TR/1998/REC-xml-19980210.http://www.w3.org/TR/1998/REC-xml-19980210 P. Buneman. Tutorial: Semistructured data. In International Conference on PODS, 1997. T. Gaasterland, P. Godfrey and J. Minker. An Overview of Cooperative Answering, Journal of Intelligent Information Systems, 1, 123-157, 1992 D. Quass, A. Rajaraman, Y. Sagiv, J. Ullman,and J. Widom. Querying semistructured heterogeneous information. In Proceedings of Deductive and Object Oriented Databases, 1995.