Schema evolution and the relational algebra

Edwin McKenzie, Richard Thomas Snodgrass

Research output: Contribution to journalArticle

41 Citations (Scopus)

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.

Original languageEnglish (US)
Pages (from-to)207-232
Number of pages26
JournalInformation Systems
Volume15
Issue number2
DOIs
StatePublished - 1990

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Algebra
Semantics
Data base
Query
Language

ASJC Scopus subject areas

  • Management Information Systems
  • Management of Technology and Innovation
  • Hardware and Architecture
  • Information Systems
  • Software

Cite this

Schema evolution and the relational algebra. / McKenzie, Edwin; Snodgrass, Richard Thomas.

In: Information Systems, Vol. 15, No. 2, 1990, p. 207-232.

Research output: Contribution to journalArticle

McKenzie, Edwin ; Snodgrass, Richard Thomas. / Schema evolution and the relational algebra. In: Information Systems. 1990 ; Vol. 15, No. 2. pp. 207-232.
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