Re: How to store temporal info?
Date: Mon, 03 Mar 2003 19:38:05 +0100
Message-ID: <b407bq$1qd9l2$1_at_ID-167942.news.dfncis.de>
On Mon, 03 Mar 2003 14:18:49 +0000, John Gilson wrote:
[...]
They had a nice summary on the site (Temporal Data and the Relational
Model, Hugh Darwen's summary of the book). I only had a glimpse at it, but
that alone gave me ideas I think I will ba able to use. To summarise,
A Resource belongs to exactly one ResourceCategory at a time. Hence the
relation:
*Resource, *ResourceCategory, *Since
will serve my needs. The problem is then reduced to finding the max(since)
<= resulttime for a given resource. Besides from not having to deal with
>
> I would second the use of the latest-representable date, instead of NULL, to
> represent a valid time that's currently valid.
>
> The Snodgrass book is quite good and complete. You might also be interested
> in the latest by Date and Darwen, "Temporal Data and the Relational Model",
> which you can find out more about at www.thethirdmanifesto.com.
>
Anyhow, thanx to both of you for your comments
/Lennart
[...]