Re: Do we always have to update or insert? Why can't we just relate?

From: Gene Wirchenko <genew_at_ucantrade.com.NOTHERE>
Date: Mon, 17 Oct 2005 10:30:33 -0700
Message-ID: <uon7l1hm8l1lpc6drkk6ujuc7k6dorqip0@4ax.com>

On 16 Oct 2005 16:37:22 -0700, "Marshall Spight" <marshall.spight_at_gmail.com> wrote:

[snip]

>If I have a gripe with SQL's update operators, it would be
>that INSERT blows up if the row is already there. Why? I
>mean, you would certainly want to fail if there was already
>a different row with the same key, because that's clearly
>an error, but why if it's the exact same row? Nothing in
>error about that.

There is: duplication of PK. Second, a set, by definition, can not contain duplicates. Does including a fact twice make it more true?

If something can appear only once, it makes certain optimisations possible.

[snip]

Sincerely,

Gene Wirchenko Received on Mon Oct 17 2005 - 12:30:33 CDT