From: Gnanavel S <s.gnanavel@gmail.com>
To: Gary Stainburn <gary.stainburn@ringways.co.uk>
Cc: pgsql-sql@postgresql.org
Subject: Re: diary constraints
Date: Tue, 23 Aug 2005 14:30:10 +0530
Message-ID: <eec3b03c0508230200127dd262@mail.gmail.com> (raw)
In-Reply-To: <200508230933.59043.gary.stainburn@ringways.co.uk>
References: <200508230933.59043.gary.stainburn@ringways.co.uk>
On 8/23/05, Gary Stainburn <gary.stainburn@ringways.co.uk> wrote:
>
> Hi folks
>
> I know this has been discussed in the past, but no amount of keywords
> has returned anything from the archives.
>
> 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
check constraint like -> "finish_time > start_time" this will do
b) two allocations for a single vehicle don't overlap.
Use "overlaps" function in a trigger to validate the above.
--
> Gary Stainburn
>
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--
with regards,
S.Gnanavel
Satyam Computer Services Ltd.
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To: pgsql-sql@postgresql.org
Cc: s.gnanavel@gmail.com, gary.stainburn@ringways.co.uk
Subject: Re: diary constraints
In-Reply-To: <eec3b03c0508230200127dd262@mail.gmail.com>
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