Re: Identity modelling
Date: 31 Aug 2005 07:49:19 -0700
Message-ID: <1125499759.244719.293100_at_g43g2000cwa.googlegroups.com>
x wrote:
>
> Let's try to use RM for this little problem:
> - the URL is a value
> - the content of the resource is a value
> - there is a relation At(URL, Content) where URL is the primary key with
> At(u,c) meaning that at this instant the URL u point to the content c.
>
> So the URL is a key after all. :-)
I have to disagree. Note that you can't map your above example onto keys in a relational table, since there is no analog to the separate (key, content) relation.
The distinguishing characteristic of content-based addressing is that data is addressed by some part of the data. Note that nothing *in* the html file identifies the html file. Most html files don't contain their url. So the URL is a pointer.
Marshall Received on Wed Aug 31 2005 - 16:49:19 CEST