Identification, genericity and consistency in object-oriented databases

  • Klaus-Dieter Schewe
  • Joachim W. Schmidt
  • Ingrid Wetzel
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 646)

Abstract

It is claimed that object-oriented databases overcome many of the limitations of the relational data model especially by generalizing the notion of object identification. A clear distinction between objects and values turns out to be essential for the object-oriented approach whereas the relational model is based exclusively on values. Since, however, value uniqueness within scopes is a quite natural constraint for a wide class of applications, identification by value is also of interest for object-oriented datamodels.

Hence, in this paper we concentrate on those classes where the extents are completely representable by values. We formalize some basic concepts of object-oriented databases and show that the finiteness of a database and the existence of finitely representable recursive types are sufficient to decide value-representability.

Another advantage of the relational approach is the existence of structurally determined canonical update operations. We show that this property can be carried over to object-oriented datamodels iff classes are value-representable. Moreover, in this case database consistency with respect to implicitly specified referential and inclusion constraints will be automatically preserved.

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Copyright information

© Springer-Verlag 1992

Authors and Affiliations

  • Klaus-Dieter Schewe
    • 1
  • Joachim W. Schmidt
    • 1
  • Ingrid Wetzel
    • 1
  1. 1.Dept. of Computer ScienceUniversity of HamburgHamburg 54

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