Designing Functional Dependencies for XML

  • Mong Li Lee
  • Tok Wang Ling
  • Wai Lup Low
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 2287)


Functional dependencies are an integral part of database theory and they form the basis for normalizing relational tables up to BCNF. With the increasing relevance of the data-centric aspects of XML, it is pertinent to study functional dependencies in the context of XML, which will form the basis for further studies into XML keys and normalization. In this work, we investigate the design of functional dependencies in XML databases. We propose FD XML , a notation and DTD for representing functional dependencies in XML. We observe that many databases are hierarchical in nature and the corresponding nested XML data1 may inevitably contain redundancy. We develop a model based on FD XML to estimate the amount of data replication in XML data. We show how functional dependencies in XML can be verified with a single pass through the XML data, and present supporting experimental results. A platformindependent framework is also drawn up to demonstrate how the techniques proposed in this work can enrich the semantics of XML.


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  1. Arm74.
    W. W. Armstrong. Dependency Structures of Database Relationships. In Proceedings of the tri-annual IFIP Conf 74, N-H (Amsterdam), 1974.Google Scholar
  2. BDF+01.
    Peter Bunemana, Susan Davidson, Wenfei Fan, Carmem Hara, and Wang-Chiew Tan. Keys for XML. In Proceedings of the WWW’10, Hong Kong, China, 2001.Google Scholar
  3. Ber76.
    P. A. Bernstein. Synthesizing Third Normal Form Relations from Functional Dependencies. ACM Transactions on Database Systems, 1(4):277–298, Dec 1976.CrossRefGoogle Scholar
  4. BPSMM00.
    Tim Bray, Jean Paoli, C. M. Sperberg-McQueen, and Eve Maler. Extensible arkup Language (XML) 1.0 (Second Edition)., 2000.
  5. CD99.
    James Clark and Steve DeRose. XML Path Language (XPath) Version 1.0. Available at, 1999.
  6. Cod70.
    E. F. Codd. A Relational Model of Data for Large Shared Data Banks. j-CACM, 13(6):377–387, June 1970.zbMATHGoogle Scholar
  7. Cod72.
    E. F. Codd. Further Normalization of the Database Relational Model. R. Rustin, Ed. Prentice-Hall, Englewood Cliffs, NJ, 1972.Google Scholar
  8. Don00.
    Dongwon Lee and Wesley W. Chu. Comparative Analysis of Six XML Schema Languages. SIGMOD Record, 29(3):76–87, 2000.CrossRefGoogle Scholar
  9. Fal00.
    D. Fallside. XML Schema Part 0: Primer. Available at, 2000.
  10. FR01.
    Mary Fernandez and Jonathan Robie. XML Query Data Model. W3C Working Draft. Available at, 2001.
  11. FS00.
    W Fan and J Siméon. Integrity Constraints for XML. In Proceedings of the Nineteenth ACM SIGMOD-SIGACT-SIGART Symposium on Principles of Database Systems, Dallas, Texas, USA, pages 23–34. ACM, 2000.Google Scholar
  12. LC00.
    Dongwon Lee and Wesley W. Chu. Constraints-Preserving Transformation from XML Document Type Definition to Relational Schema. In Proceedings of the 19th International Conference on Conceptual Modeling, pages 323–338, 2000.Google Scholar
  13. Ley01.
    Michael Ley. DBLP Bibliography. Available at, 2001.
  14. LGL96.
    Tok Wang Ling, Cheng Hian Goh, and Mong Li Lee. Extending classical functional dependencies for physical database design. Information and Software Technology, 9(38):601–608, 1996.CrossRefGoogle Scholar
  15. MAG+97.
    J. McHugh, S. Abiteboul, R. Goldman, D. Quass, and J. Widom. Lore: A Database Management System for Semistructured Data. SIGMOD Record, 26(3), 1997.Google Scholar
  16. Meg01.
    David Megginson. SAX: The Simple API for XML. Available at, 2001.
  17. TF82.
    Tsou and Fischer. Decomposition of a Relation Scheme into Boyce-Codd Normal Form. SIGACTN: SIGACT News, 14, 1982.Google Scholar
  18. W+00.
    Kevin Williams et al. Professional XML Databases. Wrox Press Inc, 2000.Google Scholar
  19. W3C01.
    W3C DOM Working Group. Document Object Model (DOM). Available at, 2001.
  20. Wed92.
    Grant E. Weddell. Reasoning About Functional Dependencies Generalized for Semantic Data Models. ACM Transactions on Database Systems, 17(1):32–64, Mar 1992.CrossRefMathSciNetGoogle Scholar
  21. Wid99.
    Jennifer Widom. Data Management for XML: Research Directions. IEEE Data Engineering Bulletin, 22(3):44–52, 1999.Google Scholar
  22. WLLD01.
    Xiaoying Wu, Tok Wang Ling, Mong Li Lee, and Gillian Dobbie. Designing Semistructured Databases Using the ORA-SS Model. In Proceedings of the 2nd International Conference on Web Information Systems Engineering (WISE). IEEE Computer Society, 2001.Google Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2002

Authors and Affiliations

  • Mong Li Lee
    • 1
  • Tok Wang Ling
    • 1
  • Wai Lup Low
    • 2
  1. 1.School of ComputingNational University of SingaporeSingapore
  2. 2.DSO National LaboratoriesSingapore

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