A Relational Model of Data for Large Shared Data Banks

  • E. F. Codd


Future users of large data banks must be protected from having to know how the data is organized in the machine (the internal representation). A prompting service which supplies such information is not a satisfactory solution. Activities of users at terminals and most application programs should remain unaffected when the internal representation of data is changed and even when some aspects of the external representation are changed. Changes in data representation will often be needed as a result of changes in query, update, and report traffic and natural growth in the types of stored information.

Key Words and Phrases

data bank data base data structure data organization hierarchies of data networks of data relations derivability redundancy consistency composition join retrieval language predicate calculus security data integrity 

CR Categories

3.70 3.73 3.75 4.20 4.22 4.29 


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  1. 1.
    CHILDS, D. L. Feasibility of a set-theoretical data structure—a general structure based on a reconstituted definition of relation. Proc. IFIP Cong., 1968, North Holland Pub. Co., Amsterdam, p. 162–172.Google Scholar
  2. 2.
    LEVEIN, R. E., AND MARON, M. E. A computer system for inference execution and data retrieval. Comm. ACM 10, 11 (Nov. 1967), 715–721.CrossRefGoogle Scholar
  3. 3.
    BACHMAN, C. W. Software for random access processing. Datamation (Apr. 1965), 36–41.Google Scholar
  4. 4.
    MCGEE, W. C. Generalized file processing. In Annual Review in Automatic Programming 6, 13, Pergamon Press, New York, 1969, pp. 77–149.Google Scholar
  5. 5.
    Information Management System/360, Application Description Manual H20–0524–1. IBM Corp., White Plains, N. Y., July 1968.Google Scholar
  6. 6.
    GIS (Generalized Information System), Application Description Manual H20–0574. IBM Corp., White Plains, N. Y., 1965.Google Scholar
  7. 7.
    BLEIER, R. E. Treating hierarchical data structures in the SDC time-shared data management system (TDMS). Proc. ACM 22nd Nat. Conf., 1967, MDI Publications, Wayne, Pa., pp. 41–49.Google Scholar
  8. 8.
    IDS Reference Manual GE 625/635, GE Inform. Sys. Div.,Pheonix, Ariz., CPB 1093B, Feb. 1968.Google Scholar
  9. 9.
    CHURCH, A. An Introduction to Mathematical Logic I. Princeton U. Press, Princeton, N.J., 1956.Google Scholar
  10. 10.
    FELDMAN, J. A., AND ROVNER, P. D. An Algol-based associative language. Stanford Artificial Intelligence Rep. AI-66, Aug. 1, 1968.Google Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2002

Authors and Affiliations

  • E. F. Codd
    • 1
  1. 1.IBM Research LaboratorySan JoseUSA

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