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Re: model inherited object

From: <deja_at_2bytes.co.uk>
Date: 21 Jun 2006 09:10:51 -0700
Message-ID: <1150906251.596690.77100@y41g2000cwy.googlegroups.com>


> I personally cannot imagine that you really *need* this.

you may well be right but I'm not sure how to store the data. In my real world scenario I have many databases that want access to some relatively static data that is relevant to all of them i.e Location. Each of these database represents a period in time, 2005, 2006 etc and the locations will remain pretty much the same. But say LOC01 has 200 sq ft in 2005 but in 2007 (because of building work) it will have 400 sq ft. However it also has 2 toilets (which have not changed because of the work).

So I record tuple X as (ID,Sq Ft, Toilets, ValidFrom) as LOC01 - 200 - 2 - 2005.
Because of the building work I will record tuple Y as LOC01 - 400 - 2 - 2005 but in fact those 2 toilets are inherited and should be reflected if I ever update the 2005 record. ALSO I want the 2006 database to show me the relevant details (which in this case is 200 sq ft and 2 toilets because it hasn't changed since 2005).

So, how should this be done? I don't think it matters particularly on how I propagate the data to the period databases (either by replication, triggers or just by views on the static data). The problem is how to model it in the "static data" db - ok, not totally static but more so than the rest of it!)

Thanks for any advice Received on Wed Jun 21 2006 - 11:10:51 CDT

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