Transitioning Temporal Support in TSQL2 to SQL3
Richard Thomas Snodgrass, Copyright Richard, T. Snodgrass, T. Snodgrass, Christian S. Jensen, Christian S. Jensen, Christian S. Jensen, Andreas Steiner, Andreas Steiner, Michael H. Böhlen, Michael H. Böhlen, Michael H. Böhlen, Michael H. Böhlen, Renato Busatto, Heidi Gregersen, Christian S. Jensen (codirector, Kristian Torp, Anindya Datta, Richard T. Snodgrass (codirector, Curtis Dyreson · 1997
This document summarizes the proposals before the SQL3 committees to allow the addition of tables with valid-time and transaction-time support into SQL/Temporal, and explains how to use these facilities to migrate smoothly from a conventional relational system to one encompassing temporal support. Initially, important requirements to a temporal system that may facilitate such a transition are motivated and discussed. The proposal then describes the language additions necessary to add valid-time support to SQL3 while fulfilling these requirements. The constructs of the language are divided into four levels, with each level adding increased temporal functionality to its predecessor. A prototype system implementing these constructs on top of a conventional DBMS is publicly available.