Skip to main content
SpringerLink
Log in

Indexed Sequential Access Method

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

  • 61 Accesses

Synonyms

Indexed sequential file; ISAM; ISAM file

Definition

An indexed sequential access method is a static, hierarchical, disk-based index structure that enables both (single-dimensional) range and membership queries on an ordered data file. The records of the data file are stored in sequential order according to some data attribute(s). Since ISAM is static, it does not change its structure if records are added or deleted from the data file. Should new records be inserted into the data file, they are stored in an overflow area. Deleted records are removed from the file (leaving empty space).

Historical Background

Although transparent for the user of a DBMS, access methods play a key role in database performance. A major performance goal of a DBMS is to minimize the number of I/Os (i.e., blocks or pages transferred) between the disk and main memory. One way to achieve this goal is to minimize the number of I/Os when answering queries. Note that many queries reference only a small...

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

Access this chapter

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 4,499.99
Price excludes VAT (USA)
  • Available as EPUB and PDF
  • Read on any device
  • Instant download
  • Own it forever
Hardcover Book
USD 6,499.99
Price excludes VAT (USA)
  • Durable hardcover edition
  • Dispatched in 3 to 5 business days
  • Free shipping worldwide - see info

Tax calculation will be finalised at checkout

Purchases are for personal use only

Institutional subscriptions

Recommended Reading

  1. Bayer R, McCreight E. Organization and maintenance of large ordered indexes. Acta Informatica. 1972;1(3):173–83.

    Article  MATH  Google Scholar 

  2. Behymer JA, Ogilive RA, Merten AG. Analysis of indexed sequential and direct access file organizations. In: Proceedings of the 1974 ACM SIGFIDET (SIGMOD) Workshop on Data Description, Access and Control; 1974. p. 186–212.

    Google Scholar 

  3. IBM Corporation. IBM system/360 operating system data management services. 2nd ed. 1972. C26-3746-1.

    Google Scholar 

  4. Keehn DG, Lacy SO. VSAM data set design parameters. IBM Syst J. 1974;13(3):186–212.

    Article  Google Scholar 

  5. Larson P. Analysis of index-sequential files with overflow chaining. ACM Trans Database Syst. 1981;6(4):671–80.

    Article  MathSciNet  Google Scholar 

  6. Mullin JK. An improved index sequential access method using hashed overflow. Commun ACM. 1972;15(5):301–7.

    Article  MATH  Google Scholar 

  7. Wong KF, Strauss JG. An analysis of ISAM performance improvement options. Manag Datamat J. 1975;4(3):95–107.

    Google Scholar 

Download references

Author information

Authors and Affiliations

  1. University of Athens, Athens, Greece

    Alex Delis

  2. University of California-Riverside, Riverside, CA, USA

    Vassilis J. Tsotras

Authors
  1. Alex Delis
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Vassilis J. Tsotras
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Alex Delis .

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

Section Editor information

  1. University of California-Riverside, Riverside, MA, USA

    Vassilis J. Tsotras

Rights and permissions

Reprints and permissions

Copyright information

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

About this entry

Check for updates. Verify currency and authenticity via CrossMark

Cite this entry

Delis, A., Tsotras, V.J. (2018). Indexed Sequential Access Method. 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_738

Download citation

Publish with us

Policies and ethics

Search

Navigation