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Uniqueness conditions for ER representations

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OOER '95: Object-Oriented and Entity-Relationship Modeling (ER 1995)

Part of the book series: Lecture Notes in Computer Science ((LNCS,volume 1021))

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Abstract

Given a collection of entity types (database tables) there is usually more than one way to model their associations. Consequently two data models may appear different while essentially they are the same. To simplify the task of comparing data models, necessary and sufficient conditions are defined for a collection of entity types to have a unique Entity Relationship Diagram. The sufficient conditions for uniqueness are translated into modeling constraints that can be easily used to build an Entity-Relationship model. It is shown that the constraints do not prevent the representation of information requirements except for rare types of involuted relationships that seldom appear in the real world. All of this is done under the assumption that relationships are degree 2 or less. The results are extended to models containing relationships of higher degree.

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Authors and Affiliations

  1. Texas Instruments Canada Ltd., 5160 Yonge St. Ste. 1315, M2N 6L9, North York, Ontario, Canada

    John L. Knapp

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  1. John L. Knapp
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Michael P. Papazoglou

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© 1995 Springer-Verlag Berlin Heidelberg

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Knapp, J.L. (1995). Uniqueness conditions for ER representations. In: Papazoglou, M.P. (eds) OOER '95: Object-Oriented and Entity-Relationship Modeling. ER 1995. Lecture Notes in Computer Science, vol 1021. Springer, Berlin, Heidelberg. https://doi.org/10.1007/BFb0020541

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  • DOI: https://doi.org/10.1007/BFb0020541

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  • Publisher Name: Springer, Berlin, Heidelberg

  • Print ISBN: 978-3-540-60672-7

  • Online ISBN: 978-3-540-48527-8

  • eBook Packages: Springer Book Archive

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