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Universal and representative instances using unmarked nulls

  • Session 6 Data Bases
  • Conference paper
  • First Online:
Foundations of Software Technology and Theoretical Computer Science (FSTTCS 1984)

Part of the book series: Lecture Notes in Computer Science ((LNCS,volume 181))

Abstract

Representative instances are important since in addition to the universal relation view they permit updates in the individual relations; if these updates are locally valid, then they do not violate global consistency. In this paper, we first give conditions under which we can construct a universal instance I which uses only one type of nulls (unmarked nulls) and whose total projections onto the relation schemes yield exactly the database relations. Then, we give a necessary and sufficient condition under which this I is actually a representative instance. Our conditions are simple and easily maintained.

This work was supported in part by the University of Missouri Summer Research Fellowship.

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Authors and Affiliations

  1. Department of Computer Science, University of Missouri-Columbia, 65211, Columbia, Missouri

    Sushil Jajodia

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  1. Sushil Jajodia
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Mathai Joseph Rudrapatna Shyamasundar

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© 1984 Springer-Verlag Berlin Heidelberg

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Jajodia, S. (1984). Universal and representative instances using unmarked nulls. In: Joseph, M., Shyamasundar, R. (eds) Foundations of Software Technology and Theoretical Computer Science. FSTTCS 1984. Lecture Notes in Computer Science, vol 181. Springer, Berlin, Heidelberg. https://doi.org/10.1007/3-540-13883-8_83

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  • DOI: https://doi.org/10.1007/3-540-13883-8_83

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  • Publisher Name: Springer, Berlin, Heidelberg

  • Print ISBN: 978-3-540-13883-9

  • Online ISBN: 978-3-540-39087-9

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