Re: temporal nature of T-box (and A-box), and why bNodes should rarely (if ever!) be used

Ted,

On Mar 8, 2011, at 16:20 , Ted Thibodeau Jr wrote:

[snip]
> 
> But these connections *cannot* be drawn when entirely ephemeral
> bNodes are used for those Entities, or Attributes, etc.  UUID-based
> dereferenceable URIs are fine for such purposes as bNodes have often
> been used -- because UUIDs are persistent over time, and each UUDI 
> can be forced to only ever refer to a single entity.  bNodes cannot
> have such restrictions placed on them ... and therein lies their doom.

I understand all that you say (and that I have cut:-) but I need a clarification for the UUID issue here. What would exactly be your URI (ie, UUID) minting algorithm here? If I do a 'run' on the database to generate a Direct Graph, I generate some sort of a URI for the row but, unless that generation of that URI is a function of the columns names or something similar, the next 'run' will produce _another_ UUID URI. So yes, a single UUID URI is persistent over time, but two independent runs on the same database, ie, two snapshots of the changes that you refer to, will produce two distinct URI-s that nothing binds to one another. Aren't we back to square one? Or maybe I miss something here.

Ivan



> 
> I hope this starts to clarify what I've been talking about in our
> concalls.  But please feel free to ask for more, or raise objections
> to anything you don't agree with.  Discussion is usually helpful.
> 
> Regards,
> 
> Ted
> 
> 
> 
> 
> 
> 
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----
Ivan Herman, W3C Semantic Web Activity Lead
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