NDLI: Holes in joins

Content Provider	Springer Nature Link
Author	Gryz, Jarek Liang, Dongming
Copyright Year	2006
Abstract	A join of two relations in real databases is usually much smaller than their Cartesian product. This means that most of the combinations of tuples in the crossproduct of the respective relations do not appear together in the join result. We characterize these combinations as ranges of attributes that do not appear together. We sketch an algorithm for finding such combinations and present experimental results from real data sets. We then explore two potential applications of this knowledge in query processing. In the first application, we model empty joins as materialized views, we show how they can be used for query optimization. In the second application, we propose a strategy that uses information about empty joins for an improved join selectivity estimation.
Starting Page	247
Ending Page	268
Page Count	22
File Format	PDF
ISSN	09259902
Journal	Journal of Intelligent Information Systems
Volume Number	26
Issue Number	3
e-ISSN	15737675
Language	English
Publisher	Kluwer Academic Publishers
Publisher Date	2006-07-21
Publisher Place	Boston
Access Restriction	One Nation One Subscription (ONOS)
Subject Keyword	Database query optimization and processing Data mining Integrity constraints Data Structures, Cryptology and Information Theory Artificial Intelligence (incl. Robotics) Document Preparation and Text Processing Business Information Systems
Content Type	Text
Resource Type	Article
Subject	Artificial Intelligence Computer Networks and Communications Information Systems Software Hardware and Architecture

Sl.	Authority	Responsibilities	Communication Details
1	Ministry of Education (GoI), Department of Higher Education	Sanctioning Authority	https://www.education.gov.in/ict-initiatives
2	Indian Institute of Technology Kharagpur	Host Institute of the Project: The host institute of the project is responsible for providing infrastructure support and hosting the project	https://www.iitkgp.ac.in
3	National Digital Library of India Office, Indian Institute of Technology Kharagpur	The administrative and infrastructural headquarters of the project	Dr. B. Sutradhar bsutra@ndl.gov.in
4	Project PI / Joint PI	Principal Investigator and Joint Principal Investigators of the project	Dr. B. Sutradhar bsutra@ndl.gov.in Prof. Saswat Chakrabarti will be added soon
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