Re: a union is always a join!
Date: Sat, 28 Mar 2009 09:51:11 -0400
Message-ID: <jXpzl.10900$%54.1374_at_nlpi070.nbdc.sbc.com>
"Walter Mitty" <wamitty_at_verizon.net> wrote in message
news:nr3zl.249$zg5.217_at_nwrddc02.gnilink.net...
>
> "Brian Selzer" <brian_at_selzer-software.com> wrote in message
> news:TJ%yl.24805$yr3.3171_at_nlpi068.nbdc.sbc.com...
>>
>> "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>
>>
>
> It's exactly the opposite, Brian. The assertion that a given state of the
> database makes different assertions about the UofD depending on how the
> database got to that state is what breaks the connection between the
> database and the UofD. It's the current state of the database, and not
> the history of the database, that makes assertions about the UofD.
>
> This is the nub of the debate between you and me. Let's let it rest here.
> I'm not going to change your mind. And you're not going to change my
> mind, or the minds of most of the participants.
>
Received on Sat Mar 28 2009 - 14:51:11 CET