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Object Identity

  • Living reference work entry
  • First Online:
Encyclopedia of Database Systems

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Synonyms

Object identifier; Object reference; OID

Definition

Object identity is a property of data that is created in the context of an object data model, where an object is assigned a unique internal object identifier, or OID. The object identifier is used to define associations between objects and to support retrieval and comparison of object-oriented data based on the internal identifier rather than the attribute values of an object.

Key Points

In an object data model, an object is created as an instance of a class. An object has an object identifier as well as a state. An object identifier is immutable, meaning that the value of the object identifier cannot change over the lifetime of the object. The state, on the other hand, is mutable, representing the attributes that describe the object and the relationships that define associations among objects. Relationships in an object data model are defined using object references based on internal object identifiers rather than attribute...

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Recommended Reading

  1. Beeri C, Thalheim B. Identification as a primitive of database models. In: Proceedings of the 7th International Workshop on Foundations of Models and Languages for Data and Objects; 1998. p. 19–36.

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  2. Koshafian S, Copeland G. Object identity. ACM SIGPLAN Not. 1986;21:406–16.

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Author information

Authors and Affiliations

  1. Arizona State University, Phoenix, AZ, USA

    Susan D. Urban & Suzanne W. Dietrich

Authors
  1. Susan D. Urban
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  2. Suzanne W. Dietrich
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Corresponding author

Correspondence to Susan D. Urban .

Editor information

Editors and Affiliations

  1. Georgia Institute of Technology College of Computing, Atlanta, Georgia, USA

    Ling Liu

  2. University of Waterloo School of Computer Science, Waterloo, Ontario, Canada

    M. Tamer Özsu

Section Editor information

  1. Brigham Young University, Provo, UT, USA

    David W. Embley

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© 2017 Springer Science+Business Media LLC

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Urban, S.D., Dietrich, S.W. (2017). Object Identity. In: Liu, L., Özsu, M. (eds) Encyclopedia of Database Systems. Springer, New York, NY. https://doi.org/10.1007/978-1-4899-7993-3_1470-2

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  • DOI: https://doi.org/10.1007/978-1-4899-7993-3_1470-2

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  • Publisher Name: Springer, New York, NY

  • Print ISBN: 978-1-4899-7993-3

  • Online ISBN: 978-1-4899-7993-3

  • eBook Packages: Springer Reference Computer SciencesReference Module Computer Science and Engineering

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