I had a chuckle when I got this. Sounds alot like multivalue to me. Stuart -----Original Message-----
The University of Melbourne Department of Computer Science and Software Engineering Seminar Tuesday, 17 August, 2004, 12:00pm Theatre 3 (ICT-205), ICT Building 111 Barry Street, Carlton Dr. Kenneth Ross Columbia University Symmetric Relations and Cardinality-Bounded Multisets in Database Systems In a binary symmetric relationship, A is related to B if and only if B is related to A. Symmetric relationships between k participating entities can be represented as multisets of cardinality k. Cardinality-bounded multisets are natural in several real-world applications. Conventional representations in relational databases suffer from several consistency and performance problems. We argue that the database system itself should provide native support for cardinality-bounded multisets. We provide techniques to be implemented by the database engine that avoid the drawbacks, and allow a schema designer to simply declare a table to be symmetric in certain attributes. We describe a compact data structure, and update methods for the structure. We describe an algebraic symmetric closure operator, and show how it can be moved around in a query plan during query optimization in order to improve performance. We describe indexing methods that allow efficient lookups on the symmetric columns. We show how to perform database normalization in the presence of symmetric relations. We provide techniques for inferring that a view is symmetric. We also describe a syntactic SQL extension that allows the succinct formulation of queries over symmetric relations. This talk represents joint work with Julia Stoyanovich. Seminars are free and open to the public. No booking is necessary. Web pages at http://www.cs.mu.oz.au/seminars/ Enquiries to Rajkumar Buyya, Seminar Coordinator [EMAIL PROTECTED] Phone: +61 3 8344-1344 Fax: +61 3 9348-1184 [See also http://www.cs.columbia.edu/%7Ekar/pubsk/symm.pdf if you're interested in the full abstract] ********************************************************************** This email message and any files transmitted with it are confidential and intended solely for the use of addressed recipient(s). If you have received this email in error please notify the Spotless IS Support Centre (61 3 9269 7555) immediately who will advise further action. This footnote also confirms that this email message has been scanned for the presence of computer viruses. ********************************************************************** ------- u2-users mailing list [EMAIL PROTECTED] To unsubscribe please visit http://listserver.u2ug.org/
