Re: Student asks about Tuples and Relations (SQL Problem)

(A copy emailed to alex also.)

In article <36379280.7EBB_at_bloomberg.net>,   kagel_at_bloomberg.net wrote:
> Alex Snoeren wrote:
> >
> > Hello,
> >
> > For a project on my university I'am investigating the possiblity of the
> > following:
> > "Is it possible to retrieve the date of when a certain tuple(record) was
> > created ?
> > Is this being saved somewhere in the RDBMS ?"
> > How can I get this date using SQL?
>
> No. Only if the table schema includes a timestamp column that is being
> maintained.
>
> Art S. Kagel
>

Art is right for oracle and I believe most commercial database products. What you are looking for is information on Temporal Databases. I know there has been research done in this area, but I don't have specific information.

So check the research indices or do a web search. In fact, a quick search at Alta Vista came up with over 900 hits including this one:

http://isse.gmu.edu/~csis/tdb/bib97/bib97.html

It's an interesting topic. This essentially adds a third dimension to relational databases (row, column, time). It could be modelled in a relational database by adding a timestamp column to all the tables and adding code (mainly triggers) to handle the work of maintaining the timestamps during sql operations. (It affects Queries as well as Inserts and Updates.)

Good luck with your investigation!

--
Ed Prochak
Magic Interface, Ltd.
440-498-3702

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