Towards a Basic Relational NF2 Algebra Processor

  • H.-J. Schek


Relations with relation-valued attributes (NF2 relations) are proposed to serve as a model for internal data structures of a data base system. A related NF2 relational algebra is described and a suitable subset of it is selected to define the interface of a basic NF2 algebra processor. It will be shown that specific projection-selection-join-sequences expressed in 1NF relations at the conceptual level are mapped to nested projection-selection sequences of the internal of NF2 relations. Costly joins therefore can be eliminated and substituted by equivalent cheaper linear queries. The selection of the subset of NF2 algebra operations is motivated by this join elimination and by the restriction to single-scan operations.


Conceptual Level Relational Algebra Address Space Nest Selection Access Path 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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  1. /AB84/.
    S. Abiteboul, N. Bidoit: Non First Normal Form Relations to Represent Hierarchically Organized Data, Proc. 3rd ACM SIGACT/SIGMOD Symp. on Princ. of Database Systems, Waterloo, Ontario, Canada, 1984Google Scholar
  2. /AMM83/.
    H. Arisawa, K. Moriya, T. Miura: Operations and Properties on Non-First Normal-Form Relational Databases, Proc. VLDB Conf., Florence, Italy, 1983Google Scholar
  3. /BRS82/.
    F. Bancilhon, P. Richard, M. Scholl: On Line Processing of Compacted Relations, Proc. VLDB Conf., Mexico City, 1982Google Scholar
  4. /DGW85/.
    U. Deppisch, J. Guenauer, G. Walch: Storage Structures and Address Techniques for the Complex Objects of the NF2 Relational Model, GI-Conference on “Data Base Systems for Office, Engineering, and Science Environments”, Karlsruhe, March 1985, (in German)Google Scholar
  5. /D0PSSW85/.
    U.Deppisch, V. Obermeit, B. Paul, H.-J. Schek, M.H. Scholl, G. Weikum: A Subsystem for the Stable Storage of Versioned Hierarchically Structured Tuples, GI-Conference on “Data Base Systems for Office, Engineering, and Science Environments”, Karlsruhe, March 1985, (in German)Google Scholar
  6. /FT83/.
    P.C. Fischer, S,J. Thomas: Operators for Non-First-Normal-Form Relations, Proc. IEEE COMPSAC, 1983Google Scholar
  7. /HL82/.
    R. Haskin, R. Lorie: On Extending the Functions of a Relational Database System, Proc. ACM SIGMOD Conf., Orlando, FL, 1982Google Scholar
  8. /Ja84/.
    G. Jaeschke: Recursive Algebra for Relations with Relation-Valued Attributes, Techn. Report No. 84.01.003 IBM Heidelberg Scientific Centre, 1984Google Scholar
  9. /JS82/.
    G. Jaeschke, H.-J. Schek: Remarks on the Algebra of Non-First-Normal-Form Relations, Proc. 1st. ACM SIGACT/SIGMOD Symp. on Princ. of Database Systems, Los Angeles, Ca. 1982Google Scholar
  10. /Ko81/.
    J. Kobayashi: An Overview of Database Management Technology, TRCS-4, SANNO College, 1753 Kamikasuya, Isehara, Kanagawa 259-11, JapanGoogle Scholar
  11. /KTT83/.
    Y.Kambayashi, K. Tanaka, K. Takeda: Synthesis of Unnormalized Relations Incorporating More Meaning, Int. Journal of Information Sciences, Special Issue on Databases, 1983Google Scholar
  12. /Lu85/.
    V. Lum, P. Dadam, R. Erbe, J. Guenauer, P. Pistor, G. Walch, H. Werner, J. Woodfill: Design of an Integrated DBMS to Support Advanced Applications, GI-Conference on “Data Base Systems for Office, Engineering, and Science”, Karlsruhe, March 1985Google Scholar
  13. /Ma77/.
    A. Makinouchi: A Consideration on Normal Form of Not-Necessarily-Normalized Relations in the Relational Data Model, Proc. VLDB Conf., Tokyo, Japan, 1977Google Scholar
  14. /SkS81/.
    M. Schkolnick, P. Sorensen: The Effects of Denormalization on Database Performance, Res. Rep. RJ3082 (38128). IBM Res. Lab., San Jose, Ca., 1981Google Scholar
  15. /SLTC82/.
    N.C. Shu, V.Y. Lum, F.C. Tung, C.L. Chang: Specification of Forms Processing and Business Procedures for Office Automation, IEEE, Trans, on Softw. Eng., Vol. SE-8:5, 1982Google Scholar
  16. /SP82/.
    H.-J. Schek, P. Pistor: Data Structures for an Integrated Database Management and Information Retrieval System, Proc. VLDB Conf., Mexico City, Mexico, 1982Google Scholar
  17. /SS83/.
    H.-J. Schek, M.H. Scholl: The NF2 Relational Algebra for a Uniform Manipulation of the External, Conceptual and Internal Data Models (in German), in: Sprachen fuer Datenbanken, J.W. Schmidt (ed.), Informatik Fachberichte Nr. 72, Springer, Berlin Heidelberg New York Tokyo, 1983Google Scholar
  18. /SS84/.
    H.-J. Schek, M.H. Scholl: An Algebra for the Relational Model with Relation Valued Attributes, Technical Report No. DVSI-1984-T1, Technical University of Darmstadt, 1984Google Scholar
  19. /U182/.
    J.D. Ullman: Principles of Database Systems, 2nd edition, Pitman, London, 1982MATHGoogle Scholar

Copyright information

© Plenum Press, New York 1987

Authors and Affiliations

  • H.-J. Schek
    • 1
  1. 1.Technical University of DarmstadtDarmstadtWest Germany

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