From: Colin Wetherbee <cww@denterprises.org>
To: Phillip Smith <phillip.smith@weatherbeeta.com.au>
Cc: pgsql-sql@postgresql.org
Subject: Re: JOIN a table twice for different values in the same query
Date: Thu, 10 Jan 2008 17:40:55 -0500
Message-ID: <47869EF7.70106@denterprises.org> (raw)
In-Reply-To: <47869C8C.4080109@denterprises.org>
References: <002f01c853d7$63bc0680$9b0014ac@wbaus090>
<47869C8C.4080109@denterprises.org>
Colin Wetherbee wrote:
> Phillip Smith wrote:
>> As a side note - all the IATA codes are unique for each airport -
>> wouldn't it be better to use these as the Primary Key and Foreign
>> Keys? Then you wouldn't have to even join the tables unless you
>> wanted the port names (not just the code)
>
> This is true, but FWIW, my application will mostly be joining for the
> name of the airport or the city, not the code.
>
> I'll keep the idea of using the codes as keys in mind, though. Thanks
> for pointing that out.
Oh, now I remember why I'm using IDs as keys. ;)
The code isn't always going to be an airport, and, for example, a train
station in Buenos Aires could conceivably have the same code as a
shipping port in Rotterdam, which, in turn, might well be JFK. :)
Colin
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To: pgsql-sql@postgresql.org
Cc: cww@denterprises.org, phillip.smith@weatherbeeta.com.au
Subject: Re: JOIN a table twice for different values in the same query
In-Reply-To: <47869EF7.70106@denterprises.org>
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