From: Michael Glaesemann <grzm@myrealbox.com>
To: Gary Stainburn <gary.stainburn@ringways.co.uk>
Cc: postgresql sql list <pgsql-sql@postgresql.org>
Subject: Re: diary constraints
Date: Tue, 23 Aug 2005 17:58:13 +0900
Message-ID: <55E1EB3D-E2CF-41FD-86AD-B39007A48BF9@myrealbox.com> (raw)
In-Reply-To: <200508230933.59043.gary.stainburn@ringways.co.uk>
References: <200508230933.59043.gary.stainburn@ringways.co.uk>
On Aug 23, 2005, at 5:33 PM, Gary Stainburn wrote:
> I want to create a courtesy car diary diary system where I have a
> table
> containing all of the cortesy cars in the pool, and then an allocation
> table which has two timestamps, one for the start date/time and one
> for
> the return date/time.
>
> How do I go about creating constraints on inserts and updates to
> ensure
> that
>
> a) the finish is after the start
> b) two allocations for a single vehicle don't overlap.
This is an interesting problem. You might want to take a look at this
book, previously mentioned on the one of the lists (by George Essig,
I believe):
> Developing Time-Oriented Database Applications in SQL
> by Richard T. Snodgrass
>
> The book is out of print, but the author has made the PDF available
> on his website at:
> http://www.cs.arizona.edu/people/rts/tdbbook.pdf
Hope this helps!
Michael Glaesemann
grzm myrealbox com
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To: pgsql-sql@postgresql.org
Cc: grzm@myrealbox.com, gary.stainburn@ringways.co.uk
Subject: Re: diary constraints
In-Reply-To: <55E1EB3D-E2CF-41FD-86AD-B39007A48BF9@myrealbox.com>
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