Title:

ORA-Semantics based Keyword Search in XML and Relational Databases

Abstract:

Keyword search in XML and relational databases (RDB) has gained popularity as it provides a user-friendly way to explore structured data. Existing works on XML and RDB keyword search only rely on the structures of XML/RDB data and/or schemas, and this causes serious problems of returning incomplete answers, meaningless answers and overwhelming answers. In this paper, we identify the problems of existing keyword search methods and point out that the main reason of these problems is due to the unawareness of the Object-Relationship-Attribute (ORA) semantics in XML/RDB. We exploit the ORA semantics in XML and RDB, and capture these semantics by constructing the Object tree for XML, and the Object-Relationship-Mixed (ORM) data graph for RDB, respectively. Based on the Object tree and the ORM data graph, we propose an ORA-Semantics based keyword search in XML and RDB. Our semantic approach can avoid the problems of existing methods and improves the completeness and correctness of keyword search. In addition, we extend the keyword query language to include keywords that match the metadata, i.e., the names of tags in XML and the names of relations and attributes in RDB. These keywords reduce the ambiguities of queries and enable us to infer users search intention more precisely. Finally, we incorporate aggregate functions and GROUPBY into keyword queries to retrieve statistical information from XML and RDB.

Bio:

   Dr. Tok Wang Ling is a professor in Computer Science Department at the National University of Singapore. He was the Head of IT Division, Deputy Head of the Department of Information Systems and Computer Science, and Vice Dean of the School of Computing of the University. Before joining the University as a lecturer in 1979, he was a scientific staff at Bell Northern Research, Ottawa, Canada. He received his PhD and M.Math., both in computer science, from University of Waterloo (Canada) and B.Sc. in Mathematics from Nanyang University (Singapore).

    His current research interests include Database Modeling, Entity-Relationship Approach, Object-Oriented Data Model, Normalization Theory, Semi-Structured Data Model, XML Twig Pattern Query Processing, XML and Relational Database Keyword Query Processing.

   He serves/served on the steering committees of 5 international conferences, including ER, DASFAA, and BigComp. He was the steering committee chair of both ER and DASFAA. He served as Conference Co-chair of 11 international conferences, including ER 2004, DASFAA 2005, SIGMOD 2007, VLDB 2010, and BigComp 2015. He served as Program Committee Co-chair of 6 international conferences, including DASFAA 1995, ER 1998, 2003, and 2011.

   He received the ACM Recognition of Service Award in 2007, the DASFAA Outstanding Contributions Award in 2010, and the Peter P. Chen Award in 2011.

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