Re: Dawn doesn't like 1NF

"Laconic2" <laconic2_at_comcast.net> wrote in message news:RrSdneqA5o2Kv-zcRVn-hQ_at_comcast.com...
>
> "Marshall Spight" <mspight_at_dnai.com> wrote in message
> news:aw8cd.268503$3l3.89210_at_attbi_s03...
>
>
> > If you don't expose pointers at the logical level, you don't have
> > to have identity comparison in your system.
>
> What follows is more thread drift, but what the heck!
>
> I've wondered whether Object Oriented systems distinguish between a "copy"
> of an object and a "clone" of an object.
>
> Here's what I mean: a copy of an object has the same class and the same
> state, but a different identity. The two objects can interact with each
> other, exchanging information, yada, yada. Over time, their states will
> diverge.
>
> A "clone" of an object had the same class, same state, and same identity,
> but a different location. Maybe the clone has been put "on ice" in a backup
> file, in case the object itself gets trashed.
>
> If the clone and the original ever start acting in the same object world,
> trouble happens. Even if they don't directly impact each other, they are
> going to mess with the other objects in the world!
>
> I'm just a babe in the woods when it comes to OO. Does the above even make
> any sense?

Kind of. I've not heard of the idea of differentiating identity and location; usually "identity" is the logical equivallent of the physical "location."

Marshall Received on Sat Oct 16 2004 - 19:41:48 CEST