Re: History, Update, Simulation

"Jochen Grefe" <jochen_at_ingenieurteam2.com> wrote in message news:8p8718$2l4$15$1_at_news.t-online.com...
> Hello,
>
> I have a database application where history updates and
> simulation should be visible to the user.
>
> If a record changes at a specific date or it is
> deleted.
> The user should be able to see the information
> in the database on any previous time.
>
> A method i tried is to integrate a time stamps
> or an id to an time stamp table in each
> record and then calcilate in an additional query
> the actual record in a table to the given time.
> Linking the query result give me then the
> hirachical database at the given time (i think so).
>
> Are there any design pattern for this. Perhaps
> I'm doing something totally wrong.

No you are not totally wrong :)
What you are trying to implement is called transaction time, and is a well known phenomena in temporal database research science. Several books and articles have been written, most of them with a very academic approach. But if you want a practical approch on how to design your system, I suggest you get a copy of Rick Snodgrass's latest book "Developing Time Oriented Database Applications in SQL", this will give you an idea of how to approch the subject.

Also you might want to try tDeveloper, this is a tool that my company is developing, which will help generate temporal constraints, views, audit trails and (in the not so distant future) queries.

Good luck :)

--
Bo Gundersen
R&D Timechain Technology
http://www.timechain.com