[12 Dec 2003]
Speaker: Ho Wai Shing
Venue: Room 328, Chow Yei Ching Building, HKU
Time: 4:30pm

DB Seminar Schedule

[19 Dec 2003]
Speaker: Ivy TONG

[2 Jan 2004]
Speaker: Kevin YIP

[9 Jan 2004]
Speaker: Edmond WU

[16 Jan 2004]
Speaker: CAO Huiping

[30 Jan 2004]
Speaker: Eric LO

[6 Feb 2004]
Speaker: Sindy SHOU

[13 Feb 2004]
Speaker: Iris ZHANG

[20 Feb 2004]
Speaker: Ken YIU

[27 Feb 2004]
Speaker: ZHANG Minghua

ViST: A Dynamic Index Method for Querying XML data by Tree Structures

Speaker: Ho Wai Shing

Abstract

With the growing importance of XML in data exchange, much research has been done in providing flexible query facilities to extract data from structured XML documents. In this paper, the authors proposed ViST, a novel index structure for searching XML documents. By representing both XML documents and XML queries in structure-encoded sequences, they showed that querying XML data is equivalent to finding subsequence matches. Unlike index methods that disassemble a query into multiple sub-queries, and then join the results of these sub-queries to provide the final answers, ViST uses tree structures as the basic unit of query to avoid expensive join operations. Furthermore, ViST provides a unified index on both content and structure of the XML documents, hence it has a performance advantage over methods indexing either just content or structure. ViST supports dynamic index update, and it relies solely on B+-Trees without using any specialized data structures that are not well supported by DBMSes. The experiments showed that ViST is effective, scalable, and efficient in supporting structural queries.