The Relational Model

  • S. M. Deen
Part of the Macmillan Computer Science Series book series


A relation is a mathematical term for a two-dimensional table such as the one shown in figure 3.15. It is characterised by rows and columns, each entry there being a data item value. The reason for calling this a relation rather than a matrix lies in the lack of homogeneity in its entries — the entries are homogeneous in the columns but not in the rows. A relational data base consists of such relations, which can be stored on a physical device in a variety of ways.


Quantity Order Unit Price Relational Algebra Common Domain Access Path 
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  1. 1.
    D. L. Childs, Proc. IFIP Congress 1968 (North Holland) p. 162.Google Scholar
  2. R. E. Levein and M. E. Maron, Communs Ass. comput. Mach., 10 (1967) p. 715.Google Scholar
  3. 2.
    For brief descriptions of these systems, see C. J.Date, An Introduction To Data Base Systems (Addison-Wesley, New York, 1975) chapter 8.Google Scholar
  4. 3.
    E. F. Codd, Communs Ass. comput. Mach., 13 (1970) p. 377.Google Scholar
  5. 4.
    E. F. Codd, Normalised Data Base Structure: A Brief Tutorial, IBM Research RJ935, November 1971.Google Scholar
  6. 5.
    E. F. Codd, Further Normalisation of the Data Base Relational Model, IBM Research RJ909, August 1971.Google Scholar
  7. 6.
    E. F. Codd, A Data Base Sublanguage Founded on the Relational Calculus, IBM Research RJ893, July 1971.CrossRefGoogle Scholar
  8. 7.
    E. F. Codd, Relational Completeness of Data Base Sublanguages, IBM Research RJ987, March 1972.Google Scholar
  9. 8.
    E. F. Codd, Recent Investigations in Relational Data Base Systems, IBM Research RJ1385, April 1974.Google Scholar
  10. 9.
    C. W. Bachman, quoted in Computer Weekly, April 8, 1976.Google Scholar

Copyright information

© S. M. Deen 1977

Authors and Affiliations

  • S. M. Deen
    • 1
  1. 1.Department of Computing ScienceUniversity of AberdeenUK

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