Re: The C in ACID
From: paul c <toledobythesea_at_oohay.ac>
Date: Mon, 21 Aug 2006 18:08:31 GMT
Message-ID: <zEmGg.433819$Mn5.367730_at_pd7tw3no>
>
> I was under the impression the terms Correct and Consistent had
> precise, well-defined and even generally agreed upon definitions with
> respect to the relational model. For example, in CJ Date's 8th edition:
>
> "Correct implies consistent (but not the other way around) and
> inconsistent implies incorrect (but not the other way around) where by
> correct we mean the database is correct if and only if it fully
> reflects the true state of affairs in the real world"
>
> Obviously my impression was wrong.
> ...
Date: Mon, 21 Aug 2006 18:08:31 GMT
Message-ID: <zEmGg.433819$Mn5.367730_at_pd7tw3no>
Paul Mansour wrote:
> paul c wrote:
>
>> I don't see a conflict. Perhaps you see a subtlety I don't. I consider >> the facts in a db correct if they are consistent with whatever >> constraints I've specified. If a user enters an untruth, there's nothing >> the dbms can do about it, unless it has been told, eg., with >> constraints, how to recognize certain lies.
>
> I was under the impression the terms Correct and Consistent had
> precise, well-defined and even generally agreed upon definitions with
> respect to the relational model. For example, in CJ Date's 8th edition:
>
> "Correct implies consistent (but not the other way around) and
> inconsistent implies incorrect (but not the other way around) where by
> correct we mean the database is correct if and only if it fully
> reflects the true state of affairs in the real world"
>
> Obviously my impression was wrong.
> ...
I'd say your impression was inconsistent, not incorrect! ;)
Truth requires a human interpretation. Some people say xyz is a bunch of terrorists, other people say they are freedom fighters. Clearly the two groups of people require different db's, no one db can satisfy both groups.
p Received on Mon Aug 21 2006 - 20:08:31 CEST