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On 7/9/14, 5:16 PM, Stuart Yeates wrote:
> On 07/10/2014 11:58 AM, Robert Sanderson wrote:
>>
>>
>>
>>
>>         Line 1: There is a resource without a global identifier which 
>> is an
>>         Instance.
>>
>>
>>     The implication of using a blank node is not "without a global
>>     identifier" but "without a global identifier I care to supply here".
>>
>>
>> Well, okay, but that just makes it even more ridiculous:
>>
>> There is a resource without a global identifier that I care to supply
>> here (line 1), and here's its global identifier (line 2-4).
>>
>> QED? :)
>
> Yes. This is standard in RDF.
>
> Bear in mind that raw RDF data formats are aimed primarily at machines.
>
> When handling datasets orders of magnitude that the available RAM, 
> there are several useful processing modes which make radically 
> different assumptions than data processing systems we might be used 
> to. In these kinds of context what might seem trivial doesn't turn out 
> to be and conversely, some things that seem hard become significantly 
> easier. See for example https://en.wikipedia.org/wiki/Map-reduce 
> https://en.wikipedia.org/wiki/Data_stream_mining etc.

Stuart, yes, admittedly, RDF data formats are to be ingested/manipulated 
by machines. But there is also a component of linking which requires 
predictable patterns. So if you have enterprise data in RDF with a 
particular pattern for discovery of an identifier, that's fine. But if 
your data is to interact with data in a larger, more open context, then 
you cannot expect other communities to be aware of a complex pattern for 
discovery of global identifiers.

I'm no expert in SPARQL, but I am going to presume that

  http://www.example.com/books/book1
     a http://bibframe.org/vocab/Book .

Will result in more retrievals on queries for things of type 
http://bibframe.org/vocab/Book

than

     _:bnode1 a bf:Instance ;
      bf:uri _:bnode2 .
   _:bnode2 a bf:Identifier ;
      bf:identifierValue "http://www.example.com/books/book1" .

In other words, the further down you bury the key information (the URI 
for the thing) the less likely your data will be discovered and linked.

kc

>
> cheers
> stuart

-- 
Karen Coyle
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