Encyclopedia of Database Systems

2009 Edition
| Editors: LING LIU, M. TAMER ÖZSU

Sparse Index

  • Mirella M. Moro
  • Vassilis J. Tsotras
Reference work entry
DOI: https://doi.org/10.1007/978-0-387-39940-9_759

Synonyms

Definition

Consider a tree-based index on some numeric attribute A of a relation R. If an index record (of the form <search-key, pointer>) is created for some of the values that appear in attribute A, then this index is sparse.

Key Points

Tree-based indices are built on numeric attributes and maintain an order among the indexed search-key values. Hence, they provide efficient access to the records of a relation by attribute value. Consider for example an index built on attribute A of relation R. The leaf pages of the index contain index-records of the form <search-key, pointer>, where search-key corresponds to a value from the indexed attribute A and pointer points to the respective record in the indexed relation R with that attribute value. If not all distinct values that appear in R.A also appear in index records, this index is sparse, otherwise it is called dense.

A sparse index needs a way to access even the relation records with values that do not...

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Recommended Reading

  1. 1.
    Elmasri and Ramez Navathe. Shamkant B. Fundamentals of Database Systems (5th edn.). Addisson-Wesley, Reading, MA, 2007.Google Scholar
  2. 2.
    Manolopoulos, Yannis Theodoridis, and Yannis Tsotras. Vassilis J. Advanced Database Indexing. Kluwer, Dordecht, 1999.Google Scholar
  3. 3.
    Silberschatz, Avi Korth, and Henry F. S. Sudarshan Database System Concepts (5th edn.). McGraw-Hill, NY, 2006.Google Scholar

Copyright information

© Springer Science+Business Media, LLC 2009

Authors and Affiliations

  • Mirella M. Moro
    • 1
  • Vassilis J. Tsotras
    • 2
  1. 1.Federal University of Rio Grande do SulPorte AlegreBrazil
  2. 2.University of California-RiversideRiversideUSA