W3C home > Mailing lists > Public > public-lod@w3.org > April 2011

Re: Linked Data, Blank Nodes and Graph Names

From: Nathan <nathan@webr3.org>
Date: Thu, 07 Apr 2011 19:21:23 +0100
Message-ID: <4D9E00A3.3030807@webr3.org>
To: Kingsley Idehen <kidehen@openlinksw.com>
CC: Linked Data community <public-lod@w3.org>
Kingsley Idehen wrote:
> On 4/7/11 1:45 PM, Nathan wrote:
>> 4) create a subset of RDF which does have a way of differentiating 
>> blank nodes from URI-References, where each blank node is named 
>> persistently as something like ( graph-name , _:b1 ), which would 
>> allow the subset to be effectively "ground" so that all the benefits 
>> of stable names and set operations are maintained for data management, 
>> but where also it can be converted (one way) to full RDF by removing 
>> those persistent names.
>> Generally, this thread perhaps differs from others, by suggesting that 
>> rather than changing RDF, we could layer on a set of specs which cater 
>> for all linked data needs, and allow that linked data to be considered 
>> as full RDF (with existential) when needed.
>> It appears to me, that if most people would be prepared to make the 
>> trade off of loosing the [ ] syntax and anonymous objects such that 
>> you always had a usable name for each thing, and were prepared to 
>> modify and upgrade tooling to be able to use this 
>> not-quite-rdf-but-rdf-compatible thing, then we could solve many real 
>> problems here, without changing RDF itself.
>> That said, it's a trade-off, hence, do the benefits outweigh the cost 
>> for you?
> Maybe it boils down making what Blank Nodes are a lot clearer. In the 
> real-world I can assert 'existence' of something that possesses a 
> collection of characteristics without having to specifically Name the 
> Subject of my observations. I think capturing the context of the 
> assertions ultimately alleviates the pain.

I agree, however this would effectively amount to still being able to 
use "_:b1" in syntax, and that amounting to saying "something exists, 
let us call it _:b1 within G, that has..", the benefit of that being 
that you're still explicitly saying 'something' rather than 'this thing 
called <u>', but also giving it a persistent name to use /within/ a 
named g-box (and g-snaps thereof).

Filtering through to the real world, this means that somebody can select 
_:b from <g> twice and get the same results each time, or quickly 
establish that the triples contained in one graph of subrdf are equal to 
those in another graph of subrdf, and so forth.

One has to wonder, if [] had never been in turtle, would it have made 
any difference to rdf uptake.. (_: syntax doesn't count, as that still 
involves giving something a name of sorts).


Received on Thursday, 7 April 2011 18:22:29 UTC

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