Mapping Generalization and Object Sharing into Nested Relations: An ODA Implementation

  • Giovanni V. Guardalben
  • Hi. T. Srl
Conference paper


The problem of mapping object oriented database systems into a classical (or nested) relational platform has received considerable attention in recent years. In fact, relational database management systems have proven their validity in a large variety of different environments, chiefly due to their simple and provable mathematical foundations. On the other hand, object oriented database systems hold the promise of addressing the problem of complex object database applications (such as CAD, GIS, etc.). Given these facts, it seems natural to look for a link between the two different approaches to data modeling. In this paper we have tried to find ways of translating some features (i.e., inheritance, or generalization, and object sharing) of object oriented databases into (nested) relational databases. Our approach has started from the non-first normal form relational model and the translation scheme that we have devised is based on inclusion dependencies among participating nested relations. The definitions that we have obtained, have allowed us to define set operators for classes. Finally, an object oriented interpretation of the ISO-ODA standard for documents based on nested relations is described in this paper.


Relational Database Relational Algebra Composite Attribute Class Hierarchy Object Sharing 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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Copyright information

© Springer-Verlag Wien 1991

Authors and Affiliations

  • Giovanni V. Guardalben
    • 1
  • Hi. T. Srl
    • 1
  1. 1.VeronaItaly

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