Schema evolution and the relational algebra

https://doi.org/10.1016/0306-4379(90)90036-OGet rights and content

Abstract

In this paper we discuss extensions to the conventional relational algebra to support both aspects of transaction time, evolution of a database's contents and evolution of a database's schema. We define a relation's schema to be the relation's temporal signature, a function mapping the relation's attribute names onto their value domains and class, indicating the extent of support for time. We also introduce commands to change a relation, now defined as a triple consisting of a sequence of classes, a sequence of signatures, and a sequence of states. A semantic type of system is required to identify semantically incorrect expressions and to enforce consistency constraints among a relation's class, signature and state following update. We show that these extensions are applicable, without change, to historical algebras that support valid time, yielding an algebraic language for the query and update of temporal databases. The additions preserve the useful properties of the conventional algebra.

References (60)

  • R. Snodgrass et al.

    A taxonomy of time in databases

  • R. Snodgrass et al.

    Temporal databases

    IEEE Comput.

    (1986)
  • C.J. Bontempo

    Feature analysis of query-by-example

  • R. Overmyer et al.

    Implementation of a time expert in a database system

    ACM SIGMOD Rec.

    (1982)
  • J. Ben-Zvi

    The time relational model

  • J. Clifford et al.

    The historical relational data model (HRDM) and algebra based on lifespans

  • S.K. Gadia

    A homogeneous relational model and query languages for temporal databases

    ACM Trans. Database Systems

    (1988)
  • S.K. Gadia

    Toward a multihomogeneous model for a temporal database

  • N.A. Lorentzos et al.

    TRA: a model for a temporal relational algebra

  • E. McKenzie

    An algebraic language for query and update of temporal databases

  • S.B. Navathe et al.

    TSQL—A language interface for history databases

  • C.S. Yeung

    Query languages for a heterogeneous temporal database

  • M.J.C. Gordon

    The Denotational Description of Programming Languages

    (1979)
  • J.E. Stoy

    Denotational Semantics: The Scott-Strachey Approach to Programming Language Theory

    (1977)
  • D.S. Scott

    Data types as lattices

    SIAM J. Comput.

    (1976)
  • C. Strachey

    Towards a formal semantics

  • E. McKenzie et al.

    An evaluation of algebras incorporating time

  • D.A. Schmidt

    Denotational Semantics, A Methodology for Language Development

    (1986)
  • D. Maier

    The Theory of Relational Databases

    (1983)
  • Cited by (44)

    • CUDL language semantics: Updating FDB data

      2009, Journal of Systems and Software
    • Semantics of time-varying information

      1996, Information Systems
    • On periodicity in temporal databases

      1995, Information Systems
    • A variational database management system

      2021, GPCE 2021 - Proceedings of the 20th ACM SIGPLAN International Conference on Generative Programming: Concepts and Experiences, co-located with SPLASH 2021
    View all citing articles on Scopus
    View full text