Encyclopedia of Database Systems

2018 Edition
| Editors: Ling Liu, M. Tamer Özsu

Fixed Time Span

  • Christian S. Jensen
  • Richard T. Snodgrass
Reference work entry
DOI: https://doi.org/10.1007/978-1-4614-8265-9_1430

Synonyms

Constant span

Definition

A time span is fixed if it possesses the special property that its duration is independent of the assumed context.

Key Points

As an example of a fixed span, “one hour” always, assuming a setting without leap seconds, has a duration of 60 min. To see that not all spans are fixed, consider “one month,” which is a prime example of a variable span in the Gregorian calendar. The duration of this span may be any of 28, 29, 30, and 31 days, depending on the context, i.e., the specific month.

Cross-References

Recommended Reading

  1. 1.
    Bettini C, Dyreson CE, Evans WS, Snodgrass RT, Wang XS. A glossary of time granularity concepts. In: Etzion O, Jajodia S, Sripada S, editors. Temporal databases: research and practice. LNCS, vol. 1399. Berlin: Springer; 1998. p. 406–13.CrossRefGoogle Scholar
  2. 2.
    Jensen CS, Dyreson CE. A consensus glossary of temporal database concepts – February 1998 version. In: Etzion O, Jajodia S, Sripada S, editors. Temporal databases: research and practice. LNCS, vol. 1399. Berlin: Springer; 1998. p. 367–405.CrossRefGoogle Scholar

Copyright information

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

Authors and Affiliations

  1. 1.Department of Computer ScienceAalborg UniversityAalborgDenmark
  2. 2.Department of Computer ScienceUniversity of ArizonaTucsonUSA
  3. 3.Dataware VenturesTucsonUSA

Section editors and affiliations

  • Richard T. Snodgrass
    • 1
  • Christian S. Jensen
    • 2
  1. 1.University of ArizonaTucsonUSA
  2. 2.Aalborg UniversityAalborg ØstDenmark