Re: URIs and Unique IDs

On Nov 9, 2008, at 8:50 AM, Alan Ruttenberg wrote:

> I should point out that within the Open Biomedical Ontologies there is
> an explicit policy of *not* changing URIs as new versions of the
> ontology are released - for one thing that would be impractical - some
> of them are updated daily. Rather there is a policy on deprecation -
> terms that are deprecated are marked as such and kept in the ontology
> so as not to leave dangling pointers.

Term deprecation works for me. And I think there does need to be a  
single (i.e., unversioned) URI for each term, that always reflects the  
'latest semantics' of a given term. My view is  that we're really  
creating a dictionary that maps a string to a definition (crudely  
put)*, and yes the semantics/definition for a term may change over  
time, so that should be reflected in the 'latest' expression of the  
term (the one that the 'latest semantics' URI represents).

But I think there also needs to be an appreciation that the exact  
concept associated with that term is evolving over time, and each time  
it explicitly evolves, that is a slightly (or hugely, sometimes)  
different conceptualization. It isn't at all impractical to create a  
new URI for each such change, even if it changes every minute, at  
least that I can see.

What I like about this scenario is that a user can use either concept  
for the term -- the very specific versioned one, or the unversioned  
'latest' one -- according to what they want to express. I don't see  
why both concepts shouldn't be available.

I tend toward the opinion (thanks to Michael U's arguments) that  
changing the versioned URI should only occur when something about the  
term is explicitly changed -- new versions of the vocabulary, in and  
of themselves, are not sufficient.

John


* So Peter's defense of visible names resonates for me.


--------------
John Graybeal   <mailto:graybeal@mbari.org>  -- 831-775-1956
Monterey Bay Aquarium Research Institute
Marine Metadata Interoperability Project: http://marinemetadata.org

Received on Monday, 10 November 2008 05:26:28 UTC