Re: Database introduction
Date: Mon, 27 Jan 2014 15:34:42 +0100
Message-ID: <lc5qq3$117$1_at_dont-email.me>
On 2014-01-27 13:56, Max wrote:
> I'm reading "The Manga Guide to Databases" as a light introduction to
> databases.
> http://tinyurl.com/phjkd2c
>
>
> Unfortunately I can't grasp division in a relational database..
>
> This is the page that explains it:
>
> http://digilander.libero.it/maxxam99/Pics/2014-01-27_132837.jpg
>
> From what it tells me I'd make the following table(1 column):
>
> Date:
> 3/5
> 3/10
> 3/5
>
>
> Clearly I didn't understand much..
Why should 3/10 be part of the result? The problem can be formulated as "On which dates where fruit exported to both destination 12 and 23?".
As an exercise, try adding and removing destinations and think about how that affects the result.
/Lennart Received on Mon Jan 27 2014 - 15:34:42 CET