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Minimizing View Sets without Losing Query-Answering Power

Li, Chen and Bawa, Mayank and Ullman, Jeffrey D. (2001) Minimizing View Sets without Losing Query-Answering Power. In: 8th International Conference on Database Theory (ICDT 2001) , January 4-6, 2001, London, UK.


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The problem of answering queries using views has been studied extensively due to its relevance in a wide variety of data-management applications. In these applications, we often need to select a subset of views to maintain due to limited resources. In this paper, we show that traditional query containment is {\em not} a good basis for deciding whether or not a view should be selected. Instead, we should minimize the view set without losing its {\em query-answering power.} To formalize this notion, we first introduce the concept of ``p-containment.'' That is, a view set $\V$ is {\em p-contained} in another view set $\W$, if $\W$ can answer all the queries that can be answered by $\V$. We show that p-containment and the traditional query containment are {\em not} related. We then discuss how to minimize a view set while retaining its query-answering power. We develop the idea further by considering p-containment of two view sets with respect to a given set of queries, and consider their relationship in terms of maximally-contained rewritings of queries using the views.

Item Type:Conference or Workshop Item (Paper)
Additional Information:This is the camera-ready version of the paper in the ICDT 2001 proceedings. For for the long version, see 2001-1.
Uncontrolled Keywords:query-answering power, p-containment, equipotence, parameterized queries
Subjects:Computer Science > Data Warehousing
Computer Science > Databases and the Web
Computer Science > Data Integration and Mediation
Information Integration
Related URLs:Project Homepage, Project Homepage,
ID Code:719
Deposited By:Import Account
Deposited On:08 Oct 2000 17:00
Last Modified:27 Dec 2008 10:26

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