Skip to main content
SpringerLink
Log in
Book cover

Encyclopedia of Database Systems pp 3538–3539Cite as

Windows

  • Reference work entry

  • 72 Accesses

Synonyms

Logical window = Time-based window; Physical window = Tuple-based windows

Definition

Windows were introduced as part of SQL:1999 OLAP Functions. For instance, given a sequence of bids it is possible to use the following SQL:2003 statement to find the last 40 offers (the current offer and the previous 39) for item 0021:

SELECT itemID, avg(Offer)

OVER(ROWS 39 PRECEDING ORDER BY TIME)

FROM BIDS

WHERE ItemID=0021

When BIDS is instead a data stream, the “ORDER BY TIME” clause becomes redundant, and clauses such as “FOLLOWING” are often not supported in continuous query languages. However, these languages still provide a “PARTITION BY” clause (or the more traditional “GROUP BY” clause), whereby a user can specify that the average of the last 40 offers must be computed for all items, not just item 0021. In addition to entailing powerful and flexible analytical queries on ordered sequences and time-series, as in databases, windows on data streams play the key role of synopses, and...

This is a preview of subscription content, log in via an institution.

Chapter
USD   29.95
Price excludes VAT (USA)
  • Available as PDF
  • Read on any device
  • Instant download
  • Own it forever
eBook
USD   2,500.00
Price excludes VAT (USA)
  • Available as PDF
  • Read on any device
  • Instant download
  • Own it forever

Tax calculation will be finalised at checkout

Purchases are for personal use only

Learn about institutional subscriptions

Recommended Reading

  1. Bai Y. et al. A data stream language and system designed for power and extensibility. In Proc. Int. Conf. on Information and Knowledge Management, 2006, pp. 337–346.

    Google Scholar 

  2. Li J. et al. Semantics and evaluation techniques for window aggregates in data streams. In Proc. ACM SIGMOD Int. Conf. on Management of Data, 2005, pp. 311–322.

    Google Scholar 

  3. Maier D., Tucker P.A., and Garofalakis M. Filtering, punctuation, windows and synopses. In Stream Data Management, N. Chaudhry, K. Shaw, M. Abdelguerfi (eds.). Vol. 30, Kluwer, Dordecht, 2005, pp. 35–56.

    Google Scholar 

Download references

Author information

Authors and Affiliations

  1. University of California-Los Angeles, Los Angeles, CA, USA

    Carlo Zaniolo

Authors
  1. Carlo Zaniolo
    View author publications

    You can also search for this author in PubMed Google Scholar

Editor information

Editors and Affiliations

  1. College of Computing, Georgia Institute of Technology, 266 Ferst Drive, 30332-0765, Atlanta, GA, USA

    LING LIU (Professor) (Professor)

  2. Database Research Group David R. Cheriton School of Computer Science, University of Waterloo, 200 University Avenue West, N2L 3G1, Waterloo, ON, Canada

    M. TAMER ÖZSU (Professor and Director, University Research Chair) (Professor and Director, University Research Chair)

Rights and permissions

Reprints and permissions

Copyright information

© 2009 Springer Science+Business Media, LLC

About this entry

Cite this entry

Zaniolo, C. (2009). Windows. In: LIU, L., ÖZSU, M.T. (eds) Encyclopedia of Database Systems. Springer, Boston, MA. https://doi.org/10.1007/978-0-387-39940-9_469

Download citation

Publish with us

Policies and ethics

Search

Navigation