Department of Computer Science and Technology

Technical reports

Constraint enforcement in a relational database management system

Michael Robson

106 pages

This technical report is based on a dissertation submitted March 1984 by the author for the degree of Doctor of Philosophy to the University of Cambridge, St John’s College.

DOI: 10.48456/tr-62


The dissertation describes the implementation of the data structuring concept of domains, intra-tuple constraints and referential constraints in a relational database management system (DBMS). The need for constraints is discussed and it is shown how they can be used to capture some of the semantics of the database’s application. The implementation described was done within the framework of the particular DBMS CODD, the main features of which are presented.

Each class of constraint is described and it is shown how each of them is specifed to the DBMS. The descriptions of the constraints are stored in the database giving a centralised data model, which is used in the enforcement of the constraints. This data model contains descriptions not only of static structures but also of procedures to be used to maintain constraints. A detailed account is given of how each constraint is maintained.

The main focus of the dissertation is on referential constraints since inter-relational structure is an area in which relational systems are particularly weak. Referential constraints impose a network structure on the database and it is shown how referential constraints can be maintained by interpreting this network, using the data-pipelining facilities provided by CODD. It is also shown how referential constraints can be used to construct generalisation hierarchies, themselves an important data modelling tool. Further, some extensions to referential constraints, which allow them to capture more semantics, are suggested. The usefulness of referential constraints is illustrated by presenting a real database example (that of the University Computing Service), on which the ideas described in the dissertation have been tested.

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BibTeX record

  author =	 {Robson, Michael},
  title = 	 {{Constraint enforcement in a relational database management
  url = 	 {},
  institution =  {University of Cambridge, Computer Laboratory},
  doi = 	 {10.48456/tr-62},
  number = 	 {UCAM-CL-TR-62}