Developing Time-Oriented Applications in SQL | Richard T. Snodgrass

# TSQL2 Temporal Query Language

TSQL2 is a temporal extension to the SQL-92 language standard. The TSQL2 committee was formed in July, 1993 after a general invitation sent to the community. This committee consisted of Richard T. Snodgrass, Ilsoo Ahn, Gad Ariav, Don Batory, James Clifford, Curtis E. Dyreson, Christian S. Jensen, Ramez Elmasri, Fabio Grandi, Wolfgang Kä, Nick Kline, Krishna Kulkarni, Ting Y. Cliff Leung, Nikos Lorentzos, John F. Roddick, Arie Segev, Michael D. Soo, and Surynarayana M. Sripada. The committee produced a preliminary language specification the following January, which appeared in the March 1994 ACM SIGMOD Record. Based on responses to that specification, changes were made to the language, and the definitive version of the TSQL2 Language Specification was published in September, 1994 [dvi, ps, pdf]. The affiliations and e-mail addresses of the TSQL2 Language Design Committee members may be found in a separate section at the end of the language specification. A tutorial of this language appeared in the September 1994 ACM SIGMOD Record.

Associated with the language specification is a collection of commentaries which discuss design decisions, provide examples, and consider how the language may be implemented. These commentaries were originally proposals to the TSQL2 Language Design Committee. They now serve a different purpose: to provide examples of the constructs, motivate the many decisions made during the language design, and compare TSQL2 with the many other language proposals that have been made over the last fifteen years. It should be emphasized that these commentaries are not part of the TSQL2 language specification per se, but rather supplement and elaborate upon it. The language specification proper is the final word on TSQL2.

The commentaries, along with the language specification, several indexes, and other supporting material, has been published as a book,
Snodgrass, Richard T., editor, Ilsoo Ahn, Gad Ariav, Don Batory, James Clifford, Curtis E. Dyreson, Ramez Elmasri, Fabio Grandi, Christian S. Jensen, Wolfgang Kä, Nick Kline, Krishna Kulkarni, T. Y. Cliff Leung, Nikos Lorentzos, John F. Roddick, Arie Segev, Michael D. Soo and Suryanarayana M.~Sripada. The TSQL2 Temporal Query Language, Kluwer Academic Publishers, 1995, 674+xxiv pages. The TSQL2 Language Specification as it appears in the TSQL2 book is also available [ps, pdf]. The .pdf files are Adobe PDF; they can be read via the 3.0 reader, accessible at http://www.adobe.com/prodindex/acrobat/readstep.html. The .ps files are postscript files.

The evaluation commentary appears in the book in an abbreviated form; the full commentary is available here [ps, pdf]. The file tl2tsql2.pl is a Prolog program that translates allowed temporal logic to TSQL2. This program was written by Michael Boehlen <boehlen@cs.auc.dk>. He may be contacted for a paper that describes this translation. This is a rather dated version of that program. Newer versions are available at the TimeCenter software page (specifically the TimeDB and Tiger systems).

The constructs and insights of TSQL2 are being incorporated into the SQL3 language.

Correspondence may be directed to the chair of the TSQL2 Language Design Committee, Richard T.Snodgrass, Department of Computer Science, University of Arizona, Tucson, AZ 85721, rts@cs.arizona.edu.

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Last updated October 5, 1997
Richard Snodgrass (rts@cs.arizona.edu)

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Jian Yang, Department of Computer Science, University of Arizona (yangjian@cs.arizona.edu)
Jan 28, 1999 (Last Update)