Re: a union is always a join!

"Walter Mitty" <wamitty_at_verizon.net> wrote in message news:HrHxl.1597$6%.913_at_nwrddc01.gnilink.net...

<snip>

> Tegiri opined as to how an update is essentially the same thing as a
> delete
> followed by an insert. An eminently reasonable proposition,
> given that any delta in a database that can be caused by an update can
> also
> be caused by a suitable delete followed by a suitable insert.

If a user issues an insert, isn't it reasonable to assume that it concerns something that isn't already represented in the database? If a user issues a delete, isn't it reasonable to assume that it concerns something that shouldn't still be represented in the database? If a user issues an update, isn't it reasonable to assume that it concerns something that should still be represented in the database? If those assumptions are reasonable, then the assumption that an update is essentially the same thing as a delete followed by an insert isn't.

The assumption that an update is essentially the same thing as a delete followed by an insert effectively denies that there is a connection between a database and the universe of discourse. And that is just absurd.

<snip> Received on Fri Mar 27 2009 - 09:01:55 CET