Transcript Cooperative Query Answering for Semistructured data

Cooperative Query
Answering for
Semistructured data
Michael Barg
Raymond K. Wong
Reviewed by
Swetha
Jack
Christian (Absent)
Chris
Contents
Introduction
What is Cooperative Query Answering?
Motivation
Work Done
Results with a detailed example
Summary and related work
Introduction
Semi structured data - XML
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Self describing schema
Heterogeneous data sources (combination of
schemas)
Standard XPATH query
REQUIRES ACCURATE UNDERSTANDING
OF STRUCTURE
What is Cooperative Query
Answering?
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.
Approximate or alternative information may be
more useful and less misleading to a user.
Example:
Q: “Is Sam an associate professor?”
User believes most associate professors have tenure.
Sam is not tenured. Sam is an associate professor.
A: “Yes, but he doesn’t have tenure.”
Motivation
To query XML
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Knowledge of underlying structure
Rich semantics come from structure
Documents adhering to different schema
located in same repository
Work Done
Edges -> relationships
Nodes -> elements
Algorithm is based on
traversing the graph
and scoring similarity.
Work Done (2)
Algorithm: Cooperative Query Processing
Input: Query Q, which is represented by the query tree, QT
Output: Set of ranked tuples, <result, score >
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
Result (Cont’s)
Result (Cont’s)
Related Work
Not well researched for semistructured
data
Well established in Relation Databases.
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Extending SQL Syntax
Database (CoBase)
Concept Similarities
Cooperative Interfacing
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

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Traversing through the nodes
Results is promising
Questions?
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.
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.