view determinacy for preserving selected information in data transformations

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	view determinacy for preserving selected information in data transformations
	Fan Wenfei ; Geerts Floris ; Zheng Lixiao
刊名	Information Systems
	2011
页码	-
ISSN号	3064379
英文摘要	When transforming data one often wants certain information in the data source to be preserved, i.e.,we identify parts of the source data and require these parts to be transformed without loss of information. We characterize the preservation of selected information in terms of the notions of invertibility and query preservation, in a setting when transformations are specified as a view V (a set of queries), and source information is selected by a query Q. We investigate the problem for determining whether transformations V preserve the information selected by Q. (1) We show that the notion of invertibility coincides with view determinacy studied for query rewriting. (2) We establish the undecidability of the problem when either Q or V is in DATALOG or first-order logic, for invertibility and query preservation. (3) When Q and V are conjunctive queries (CQ), the problem is as hard as view determinacy for CQ queries and CQ views, an open problem. Nevertheless, we provide complexity bounds of the problem, either in ptime or np-complete, when V ranges over subclasses of CQ (i.e.,SP, SC, PC), and when Q is assumed to be a minimal CQ query or not. (4) We show that CQ is complete for L - to - CQ rewriting when L is SP, SC or PC, i.e.,every CQ query can be rewritten in terms of SP, SC or PC views using a query in CQ. © 2011 Elsevier Ltd. All rights reserved.
收录类别	EI
语种	英语
WOS记录号	WOS:000296991000001
公开日期	2011-10-10
内容类型	期刊论文
源URL	[http://124.16.136.157/handle/311060/13987]
专题	软件研究所_软件所图书馆_期刊论文
推荐引用方式 GB/T 7714	Fan Wenfei,Geerts Floris,Zheng Lixiao. view determinacy for preserving selected information in data transformations[J]. Information Systems,2011:-.
APA	Fan Wenfei,Geerts Floris,&Zheng Lixiao.(2011).view determinacy for preserving selected information in data transformations.Information Systems,-.
MLA	Fan Wenfei,et al."view determinacy for preserving selected information in data transformations".Information Systems (2011):-.