Entity-relationship consistency for relational schemas

  • Johann A. Makowsky
  • Victor M. Markowitz
  • Nimrod Rotics
Contributed Papers
Part of the Lecture Notes in Computer Science book series (LNCS, volume 243)

Abstract

We investigate the significance of requiring from a relational schema to comply with an entity-relationship structure. Relational database schemas here consist of traditional relational schemas together with key and inclusion dependencies. Such schemas are said to be entity-relationship (ER) consistent, either if they are the translate of, or if it is possible to translate them into, entity-relationship diagrams. An algorithm is presented which decides if a schema is ER-consistent and its complexity is discussed. ER-consistency expresses information structure normalization just as relational normal forms represent data representation normalization. For ER-consistent relational schemas we propose an Entity-Relationship Normal Form, and present the corresponding normalization procedure. ER-consistency expresses the capability of relational schemas to model information oriented systems. ER-consistent relational schemas allow the direct use of ER oriented query and update languages within the relational model.

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References

  1. [1]
    C. Beeri and M.Y. Vardi, "A note on decompositions of relations databases", ACM SIGMOD Record 12,1, Oct. 1981, pp. 33–37.Google Scholar
  2. [2]
    P.P. Chen, "The entity-relationship model-towards a unified view of data", ACM Trans. on Database Systems 1,1 (March 1976), pp. 9–36.Google Scholar
  3. [3]
    E.F. Codd, "Extending the relational database model to capture more meaning", ACM Trans. on Database Systems 4,4 (Dec 1979), pp. 397–434.Google Scholar
  4. [4]
    E.F. Codd, "Relational databases: A practical foundation for productivity", Comm. ACM 25,2 (Feb 1982), pp. 109–117.Google Scholar
  5. [5]
    S.S. Cosmadakis and P.C. Kanellakis, "Equational Theories and Database Constraints", in Proc 17th ACM Symposium on Theory of Computing, 1985, pp. 273–284.Google Scholar
  6. [6]
    M.A. Casanova and J.E. Amaral de Sa, "Mapping uninterpreted schemes into entity-relationship diagrams: two applications to conceptual schema design", IBM Journal of Research and Development 28, 1 (Jan 1984), pp. 82–94.Google Scholar
  7. [7]
    M.A. Casanova and V.M.P. Vidal, "Towards a sound view integration methodology", Proc of Second ACM Symposium on Principles of Database Systems, 1983, pp. 36–47.Google Scholar
  8. [8]
    A. Klug, "Entity-relationship views over uninterpreted enterprise schemas", Entity-Relationship Approach to Systems Analysis and Design, Chen, P.P.(ed.), North-Holland, 1980, pp. 39–59.Google Scholar
  9. [9]
    H. Mannila and K-J. Raiha, "Inclusion dependencies in database design", Proc of Second Conf. on Data Engineering, 1986, pp. 713–718.Google Scholar
  10. [10]
    J.C. Mitchell, "The implication problem for functional and inclusion dependencies", Information and Control 56,3 (March 1983), pp. 154–173.Google Scholar
  11. [11]
    N. Rotics, A unifying approach to the entity-relationship and relational data models, M.Sc. Thesis, Computer Science Dept, Technion, Israel, June 1985.Google Scholar
  12. [12]
    E. Sciore, "Inclusion dependencies and the universal instance", in Proc. 1983 ACM Symposium on Principles of Database Systems, 1983, pp. 48–57.Google Scholar
  13. [13]
    D.C. Tsichritzis and F.H. Lochovsky, Data models. Prentice-Hall, 1982.Google Scholar
  14. [14]
    J.D. Ullman, Principles of database systems (second edition), Computer Science Press, 1982.Google Scholar

Copyright information

© Springer-Verlag 1986

Authors and Affiliations

  • Johann A. Makowsky
    • 1
  • Victor M. Markowitz
    • 1
  • Nimrod Rotics
    • 1
  1. 1.Computer Science DepartmentTechnion Israel Institute of TechnologyHaifa

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