From rts Thu Jul  1 09:34:27 1993
Date: Thu, 1 Jul 1993 09:31:07 MST
From: "Rick Snodgrass" <rts>
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Subject: TSQL2 working group
Content-Length: 2383
Status: RO
X-Lines: 52

In this message I outline a structure for the short term design of a
temporal extension to SQL2, and solicit members for this working
group.

The TSQL2 working group design will proceed in the context of the
following constraints.

* The initial design must be completed by August 23, 1993.

* The design will be based on SQL2. In particular, none of the
	significant extensions envisioned in SQL3 will be assumed
	to be present.

* Initially, the language design will support user-defined time and
	valid time. Support for transaction time may be added later.

* The design will be implementable in the context of conventional
	relational database technology. In particular, implementations
	of the the data model and query language constructs will be
	possible without necessitating major changes to conventional
	database management systems.

* Discrete time will be assumed.

* Past and future valid time will be supported.

The initial goal of this working group will be to develop a language
design to be included in the final workshop report which will be sent
to DARPA and to NSF and will be distributed widely to the database
and temporal DB user communities.

The activities of this working group will be parallel to those of the
SQL2/3 and TSQL3 working groups. Interaction in the medium term
interaction between these groups will attempt to arrive at consistent
approaches.

I now solicit those interested in participating in such a language
design to join this working group. While participation in this effort
will certainly entail significant effort over the next 8 weeks, there
is also much to be gained. The resulting language will be the first
consensual temporal query language, and as such, will strongly
influence TSQL3 and other longer-term query language design efforts.
Since this language will be part of the final report, it could very
well influence DARPA's activities in temporal databases.  This
consensual effort will also have visibility with the DBMS vendors, and
so could influence temporal support in future commercial products.

If you agree with me that a design of an extension to SQL2, in
parallel with the longer term design of an extension to SQL3, is an
appropriate approach, please let me know. I personally think that the
definition of TSQL2 will be a watershed event in temporal database
research, and I invite you to join in this effort.