The relational data management system: A perspective

ABSTRACT

In this paper, the functional capabilities and economic features of the Relational Data Management System (RDMS) are discussed. RDMS is a generalized on-line data management system written in PL/1 for the Multics operating system. The basic concepts of RDMS are introduced and the similarities between the conventional file concept and the relation concept are discussed. A data-base is shown to be a set of relations. By generalizing the concept of field to be a property of the data-base, and by labeling relations with the names of their columns (fields), relations of a data-base may be implicitly linked by virtue of having a common column or field name (the dataclass name). On-line commands for operations on two such relations which yield a third result relation are illustrated. Other facilities of RDMS, such as computational, report-generation, and query-report packages are discussed. In RDMS, the relation concept is implemented as a matrix of reference numbers which refer to character string datums which are stored elsewhere in distinct dataclass files. In addition to significant storage savings, this allows a single representation-independent logical interface to the storage and access of character string data. RDMS was developed from graduate work done at M.I.T. by L. A. Kraning and A. I. Fillat in 1970 and is now being used by the administrative departments at M.I.T.

REFERENCES

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INDEX TERMS

Primary Classification:
  H. Information Systems
  H.2 DATABASE MANAGEMENT
      H.2.4 Systems
          Subjects: Relational databases

Additional Classification:
  H. Information Systems
  H.2 DATABASE MANAGEMENT
      H.2.3 Languages
          Subjects: Query languages

General Terms:
Languages, Management

Keywords:
Data management, Query language, Relation, Relational data base, Report generation, Set theoretic data base