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Current Semantics

  • Reference work entry
  • First Online:
Encyclopedia of Database Systems

  • 153 Accesses

Synonyms

Temporal upward compatibility

Definition

Current semantics constrains the semantics of non-temporal statements applied to temporal databases. Specifically, current semantics requires that non-temporal statements behave as if applied to the non-temporal database that is the result of taking the timeslice of the temporal database at the current time.

Main Text

Current semantics [5] requires that queries and views on a temporal database consider the current information only and work exactly as if applied to a non-temporal database. For example, a query to determine who manages the high-salaried employees should consider the current database state only. Constraints and assertions also work exactly as before: they are applied to the current state and checked on database modification.

Database modifications are subject to the same constraint as queries: they should work exactly as if applied to a non-temporal database. Database modifications, however, also have to take into...

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References

  1. Bair J, Böhlen MH, Jensen CS, Snodgrass RT. Notions of upward compatibility of temporal query languages. Wirtschaftsinformatik. 1997;39(1):25–34.

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  2. Clifford J, Dyreson C, Isakowitz T, Jensen CS, Snodgrass RT. On the semantics of “NOW” in databases. ACM Trans Database Syst. 1997;22(2):171–214.

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  3. Kulkari K, Michels JE. Temporal features in SQL:2011. ACM SIGMOD Rec. 2012;41(3): 34–43.

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  4. Melton J, editor. ISO/IEC 9075, database language SQL:2011 Part 2: SQL/foundation, Dec 2011.

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  5. Snodgrass RT. Developing time-oriented database applications in SQL. San Francisco: Morgan Kaufmann; 1999.

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Author information

Authors and Affiliations

  1. Free University of Bozen-Bolzano, Bozen-Bolzano, Italy

    Michael H. Böhlen

  2. University of Zurich, Zürich, Switzerland

    Michael H. Böhlen

  3. Department of Computer Science, Aalborg University, Aalborg, Denmark

    Christian S. Jensen

  4. Department of Computer Science, University of Arizona, Tucson, AZ, USA

    Richard T. Snodgrass

  5. Dataware Ventures, Tucson, AZ, USA

    Richard T. Snodgrass

Authors
  1. Michael H. Böhlen
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  2. Christian S. Jensen
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  3. Richard T. Snodgrass
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Corresponding author

Correspondence to Michael H. Böhlen .

Editor information

Editors and Affiliations

  1. Georgia Institute of Technology College of Computing, Atlanta, GA, USA

    Ling Liu

  2. University of Waterloo School of Computer Science, Waterloo, ON, Canada

    M. Tamer Özsu

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© 2018 Springer Science+Business Media, LLC, part of Springer Nature

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Böhlen, M.H., Jensen, C.S., Snodgrass, R.T. (2018). Current Semantics. In: Liu, L., Özsu, M.T. (eds) Encyclopedia of Database Systems. Springer, New York, NY. https://doi.org/10.1007/978-1-4614-8265-9_1068

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