Nathan,
I'm not sure it's correct to refer to your examples as "primary" and
"secondary" resources. As you point out, it is not true that
if I remove http://www.w3.org/People/Berners-Lee/card then
http://www.w3.org/People/Berners-Lee/card#i no longer exists.
since the first URI refers to an information resource, while the second
refers to a non-information resource.
You seem to take this as an argument against fragment identifiers, but it
doesn't just apply to hash URIs. If the server www.w3.org goes down, then
all URIs that it dereferences become non-dereferenceable, whether they are
hash URIs or slash URIs.
Now, must we stop using a URI when the server that dereferences it goes
down? I think there are cases where the answer is no, where it makes sense
to continue using the URI as an identifier, even if the URI is no longer
valid as an address. In the above case, there are
many webpages making assertions about
http://www.w3.org/People/Berners-Lee/card#i ,
and those assertions are valid, regardless of the existence of
the server www.w3.org. Making thoses assertions easy to find might be a
challenge, of course, which is why I would like to see rdf browsers do
more than simply issue a GET on a URI when trying to resolve it.
Joel.
On Fri, 12 Mar 2010, Nathan wrote:
Hi Again :)
Last question(s) related to fragments.. if I have:
http://example.org/something
http://example.org/something#a
Those are two unique URIs and thus two unique resources (?)
And the semantics of a fragment means that
http://example.org/something#a is a secondary resource, where
http://example.org/something is the primary resource (?)
Then if I delete a Primary resource, the secondary resources must also
be deleted, true / false (?).
Here are some examples, which may seem like over kill but some are
interesting and generally I *feel* rules like this should be either
always true, or always false, never varying.
examples:
if I remove a database table, then all it's rows also no longer exist.
if I remove London then the Tower of London also no longer exists.
if somebody removes me, then my arms also no longer exist.
if I remove test.html then test.html#whatever no longer exists.
if I remove test.rdf then test.rdf#this no longer exists
if I remove http://www.w3.org/People/Berners-Lee/card then
http://www.w3.org/People/Berners-Lee/card#i no longer exists.
conversely:
if I remove a row, the table still exists
if I remove the Tower of London, London still exists
if you remove my arms, I still exists and I'll find another way to type.
if I remove test.html#whatever test.html still exists
if I remove test.rdf#this, test.rdf still exists
if I remove http://www.w3.org/People/Berners-Lee/card#i then
http://www.w3.org/People/Berners-Lee/card still exists.
If the above is true (secondary resource must also be deleted on removal
of primary resource), then I should never use a fragment Identifier to
refer to a non-virtual object (i.e. "me" a Person) - because I can't be
deleted by simply removing a resource. (?)
Regards!
Nathan
