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Time and Relational Theory, 2nd Edition
book

Time and Relational Theory, 2nd Edition

by C.J. Date, Hugh Darwen, Nikos Lorentzos
August 2014
Advanced content levelAdvanced
560 pages
15h 32m
English
Morgan Kaufmann
Content preview from Time and Relational Theory, 2nd Edition
Chapter 4

Time and the Database

What’s a temporal relation? What’s a temporal relvar? And what’s a temporal database? This chapter distinguishes between relational and nonrelational approaches to the temporal database issue. It discusses the fundamental notion of a timestamped proposition and the fundamental significance of the propositions on, since, and during. It also briefly explains the distinction between “valid time” and “transaction time.” Importantly, it introduces the fundamental notion of an interval as a finite sequence of points, and it discusses the related notion of granularity. Finally, it revisits The Closed World Assumption and stresses the need to be extremely careful in stating predicates when timestamps are involved.

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Publisher Resources

ISBN: 9780128006313