Encyclopedia of Database Systems

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

Join Dependency

  • Solmaz Kolahi
Reference work entry
DOI: https://doi.org/10.1007/978-1-4614-8265-9_1249

Synonyms

JD

Definition

A join dependency (JD) over a relation schema R[U] is an expression of the form ®[X1,…,Xn], where X1 ∪ … ∪ Xn = U. An instance I of R[U] satisfies ®[X1,…,Xn] if \( I={\pi}_{X_1}(I)\ddot{\mathrm{I}}\dots \ddot{\mathrm{I}}{\pi}_{X_n}(I) \)

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Recommended Reading

  1. 1.
    Abiteboul S, Hull R, Vianu V. Foundations of databases. Reading: Addison-Wesley; 1995.zbMATHGoogle Scholar

Copyright information

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

Authors and Affiliations

  1. 1.University of British ColumbiaVancouverCanada

Section editors and affiliations

  • Leonid Libkin
    • 1
  1. 1.School of InformaticsUniversity of EdinburghEdinburghUK