The VLDB Journal

, Volume 17, Issue 2, pp 333–353 | Cite as

Implementing mapping composition

  • Philip A. Bernstein
  • Todd J. Green
  • Sergey Melnik
  • Alan Nash
Special Issue Paper


Mapping composition is a fundamental operation in metadata driven applications. Given a mapping over schemas σ1 and σ2 and a mapping over schemas σ2 and σ3, the composition problem is to compute an equivalent mapping over σ1 and σ3. We describe a new composition algorithm that targets practical applications. It incorporates view unfolding. It eliminates as many σ2 symbols as possible, even if not all can be eliminated. It covers constraints expressed using arbitrary monotone relational operators and, to a lesser extent, non-monotone operators. And it introduces the new technique of left composition. We describe our implementation, explain how to extend it to support user-defined operators, and present experimental results which validate its effectiveness.


Model management Schema mappings Mapping composition 


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Copyright information

© Springer-Verlag 2007

Authors and Affiliations

  • Philip A. Bernstein
    • 1
  • Todd J. Green
    • 2
  • Sergey Melnik
    • 1
  • Alan Nash
    • 3
  1. 1.Microsoft ResearchRedmondUSA
  2. 2.University of PennsylvaniaPhiladelphiaUSA
  3. 3.IBM Almaden Research CenterSan JoseUSA

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