Compiling Away Set Containment and Intersection Joins

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URL:	https://ub-madoc.bib.uni-mannheim.de/741
URN:	urn:nbn:de:bsz:180-madoc-7412
Document Type:	Working paper
Year of publication:	2002
The title of a journal, publication series:	Technical Reports
Volume:	02-004
Place of publication:	Mannheim
Publication language:	English
Institution:	School of Business Informatics and Mathematics > Sonstige - Fakultät für Wirtschaftsinformatik und Wirtschaftsmathematik
MADOC publication series:	Veröffentlichungen der Fakultät für Mathematik und Informatik > Institut für Informatik > Technical Reports
Subject:	004 Computer science, internet
Subject headings (SWD):	Abfrageverarbeitung , Objektrelationales Datenbanksystem , Join-Operation
Keywords (English):	databases , query rewriting , join , set-valued attributes
Abstract:	We investigate the effect of query rewriting on joins involving set-valued attributes in object-relational database management systems. We show that by unnesting set-valued attributes (that are stored in an internal nested representation) prior to the actual set containment or intersection join we can improve the performance of query evaluation by an order of magnitude. By giving example query evaluation plans we show the increased possibilities for the query optimizer.