Re: what are keys and surrogates?
Date: Mon, 28 Jan 2008 10:46:32 -0400
Message-ID: <479deace$0$4050$9a566e8b_at_news.aliant.net>
David Cressey wrote:
> "Bob Badour" <bbadour_at_pei.sympatico.ca> wrote in message
> news:479d16f3$0$4055$9a566e8b_at_news.aliant.net...
>
>>Logical representations are representations to users. Physical
>>representations are representations to the machine.
>
> The trouble with this definition is that the user of a machine is frequently
> another machine.
> For example, the "user" of a database is frequently an application program.
> That application program is a machine. It has users.
I fail to see a point in what you wrote.
To the users of the
> app, the "logical level" is the representation they see. The "physical
> representation" is the representation to the app.
Within the app, yes. But that is beyond the scope of systematically managed data. I don't know why you would even mention such an irrelevancy.
[snip] Received on Mon Jan 28 2008 - 15:46:32 CET