TSQL2 and SQL3 Interactions

Richard T. Snodgrass

republished from the

Various members of the temporal database research community are working to transfer some of the constructs and insights of TSQL2 into SQL3. The first step was to propose a new part to SQL3, termed SQL/Temporal. This new part was accepted at the Ottawa meeting in January, 1995 as Part 7 of the SQL3 specification. A modification of TSQL2's PERIOD data type is included in that part.

Discussions then commenced on adding valid-time and transaction-time support to SQL/Temporal. Two change proposals, ANSI-96-501 and ANSI-96-502, were unanimously accepted by ANSI and forwarded to ISO. These proposals have not yet been voted on by the ISO committee, because that body is busy finalizing SQL/Foundation as an international standard. A discussion of these proposals may be found in "Transitioning Temporal Support in TSQL2 to SQL3," by R. T. Snodgrass, M. H. Bohlen, C. S. Jensen, and A. Steiner, in Temporal Databases: Research and Practice, O. Etzion, S. Jajodia, and S. Sripada (eds.), Springer, pp. 150-194, 1998.

A prototype implementation of the proposed constructs has been developed by Andreas Steiner and Michael Boehlen: TimeDB.

The base document for Part 7, SQL/Temporal, against which further change proposals are directed, is edited by Jim Melton. Some ISO SQL3 documents are available at Some ANSI documents are available at ANSI and ISO documents have the following prefixes.

The general procedure is that change proposals are first directed towards a national committee (i.e., ANSI X3H2), which then decides whether to forward the proposal to the international committee (ISO/IEC JTC 1/SC 21/WG 3 DBL).

The .pdf files are Adobe PDF; they can be read via the 3.0 reader, accessible at The .ps files are postscript files.

ANSI documents

ISO documents

More information on this effort may be requested from Richard Snodgrass,
Last updated June 18, 1998
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