Searching for compositions in ER schemes

  • Otto Rauh
  • Eberhard Stickel
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 823)


Absence of redundancy is an important quality of ER schemata. Adequate treatment of derivable data, in addition to observing normal forms, is necessary to achieve nonredundant databases. According to the source of their meaning to the user, there are two types of derivable data which should be treated differently. M-derivable data are redundant und ought to be removed from the ER schema, whereas s-derivable data add knowledge to the database and may be kept in the schema if they are distinguished from original data. However, there are some classes of derivable data, which are often brought into an ER schema unintentionally and are hard to detect. We introduce an important class of such data, compositions of relationship sets, and define them formally. In addition, we suggest methods which might help the database designer to find compositions in the schema.


Normal Form Binary Relation Composition Operator General Composition Derivation Rule 
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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Copyright information

© Springer-Verlag Berlin Heidelberg 1994

Authors and Affiliations

  • Otto Rauh
    • 1
  • Eberhard Stickel
    • 2
  1. 1.Fachhochschule HeilbronnKünzelsau
  2. 2.Europa-Universität Viadrina Frankfurt/OderFrankfurt/Oder

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