For CouchDB, I think UUIDs are clearly the way to go. After all, given
the UUID, database, and hostname, you can construct the desired URL
directly by forming
http://hostname:5984/database/UUID
As Noah points out, if you used this entire URL as the identifier (by
which I assume he means the _id field), then you would lose the ability
to copy the document elsewhere. This would, of course, break
replication completely.
Keeping the UUIDs as they are gives the best of both worlds. Easy
replication, and (as long as the database is hosted at the same place)
an easy way for humans and programs to construct stable URIs or URLs
that point to each document.
-- Kevin
On 1/22/2012 12:44 PM, Noah Slater wrote:
Sorry to bump this old thread, but just going through my backlog.
With regard to URLs, I think there is some confusion about the purpose of a
URL here.
If I write a a cool essay, say, and I stick that up at
nslater.org/my-cool-essay, then I can link to it from other places on the
web using that address. I might also want to put my cool essay on Dropbox,
or post it to Tumblr, or send it in an email. Now my cool essay has lots of
URLs. Each one of them perfectly valid. I don't have to go and edit the
original copy at nslater.org/my-cool-essay, because I am making copies of
it. My cool essay is completely unaware of the URLs that are being used to
point to it. And it doesn't care that many URLs point to it.
Yes, URLs can be used as identifiers. But when you do this, you tie the
thing you're naming to the place you're hosting it. Sometimes that is
useful, other times it will cripple you. There is nothing about URLs that
requires you to do this. I would hazard a guess that 99% of URLs are
de-coupled from the things they point to. WebArch is much more robust when
the identity of the object is de-coupled from the URL. Look at Atom, the ID
element is supposed to be a URL, but they recommend a non-dereferencable
format, precisely to decouple posts from the location you happen to be
hosting them this month.
Hey, if we're gonna use URLs, maybe we want to go down the same route?
http://en.wikipedia.org/wiki/Tag_URI
At this point, I'm not sure what they buy us over UUIDs.
Thoughts?
Thanks,
N
