From: | Colin Wetherbee <cww(at)denterprises(dot)org> |
---|---|
To: | Phillip Smith <phillip(dot)smith(at)weatherbeeta(dot)com(dot)au> |
Cc: | pgsql-sql(at)postgresql(dot)org |
Subject: | Re: JOIN a table twice for different values in the same query |
Date: | 2008-01-10 22:40:55 |
Message-ID: | 47869EF7.70106@denterprises.org |
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Lists: | pgsql-sql |
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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