Re: temporary urn:predicates

On 13 July 2015 at 16:42, Urs Holzer <urs@andonyar.com> wrote:

> On Mon, Jul 13, 2015 at 03:51:11PM +0200, Melvin Carvalho wrote:
> > On 13 July 2015 at 15:42, Urs Holzer <urs@andonyar.com> wrote:
> >
> > > On Tue, Jun 30, 2015 at 04:59:29PM +0200, Melvin Carvalho wrote:
> > > > I was talking recently about barriers to producing semantic web data.
> > > >
> > > > Normally a predicate has to be
> > > >
> > > > - A URI
> > > > - Preferably an HTTP URI
> > > > - Preferably an existing URI
> > > >
> > > > This (Im told) can be a barrier for newcomers.  They have to find the
> > > right
> > > > name for a predicate, the right URI, and then see if it's already
> used.
> > > If
> > > > not create their own vocabulary.
> > > >
> > > > At this point some might give up.
> > > >
> > > > So I was wondering how it might be possible to create a temporary URI
> > > that
> > > > people could use as a place holder, so the software still works,
> until
> > > they
> > > > think of a better name.
> > > > [...]
> > >
> > > One can use a UUID URN as a namespace:
> http://tools.ietf.org/html/rfc4122
> > > For example <urn:uuid:19b75eab-77bd-46a7-a9c6-1ff0fd135a56#>
> > >
> >
> > Thanks, yes I use this.
> >
> >
> > >
> > > There is also a URN namespace for examples:
> > > http://tools.ietf.org/html/rfc6963
> > >
> > >
> > It seems to me that when a variable is "just a name" then urn: as a URI
> > being "just a name" seems a very good fit.
> >
> > I've had a look at some, but not all, of the sub namespaces within URN.
> It
> > seems hard to pick one over the other, and that the top level of urn: was
> > designed for exactly this use case, and therefore, could be the easiest
> > place to build consensus around ... I could be wrong!
>
> http://tools.ietf.org/html/rfc2141 indicates to me that a urn needs a
> namespaces identifier (and consequently contains at least two colons).
> The required Syntax is
>         <URN> ::= "urn:" <NID> ":" <NSS>
> So, I would not use <urn:>.
>
> http://tools.ietf.org/html/rfc3406 reserves all URN namespaces beginning
> with X- for experimental purposes.
>

what about

urn:tmp:<variable>


>
> Finally you could also coin your own URI scheme, for example <private:>,
> but see http://tools.ietf.org/html/rfc7595#section-3.8
>
> I would suggest <example:> if the data is not published before removing
> all <example:> with proper URIs. Otherwise, if it is used in a larger
> context and the temporary URIs are replaced gradually, I would use UUID
> URNs ensuring uniqueness. <example:> has the advantage that one can
> locate them with a simple search. A URN may always be legitimate, so it
> would become more difficult later on to find out which URIs still have
> to be replaced with proper ones.
>