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On 8/1/14, 8:55 AM, Ford, Kevin wrote:
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I know that there is a
tendency to "go blank" when punting on the decision URI/literal, but then
you need to make some other adjustments in your design. 
-- The actual decision is between a resource and a literal, not a URI and a literal (or a "blank node" and a literal). 

No, actually, literals ARE resources in RDF - From the RDF documentation:

" Any IRI or literal denotes something in the world (the "universe of discourse"). These things are called resources. " [1]

So I probably should have said "IRI or literal", but haven't yet made "IRI" the habit that "URI" is.

Perhaps we could standardize here on "thing or string" to make things clearer?

kc

[1] http://www.w3.org/TR/2014/REC-rdf11-concepts-20140225/#resources-and-statements

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 A blank node represents an anonymous resource, but that resource could just as easily had been identified by a URI.  It's ultimately a choice by the implementer.  Now, blank nodes show up a lot because that is a typical side-effect of a first pass at the data, when one does not actually know of a URI that could be used instead.

About this

As I've already
shown, the use of label in multiple places in the data within blank nodes
makes it very hard to retrieve the desired data:
and this

This search does not
work on triples with blank nodes:

SELECT ?subject ?label
      WHERE { ?subject bf:providerName ?bnode .
                   ?bnode bf:label ?label . }
-- You've presented these conclusions before.  I do not know if I understand the first statement, but I believe the second quote is used as evidence of the first and I believe the second thing I quoted to simply be wrong.  The query, when run against data with blank nodes, works just fine for me and I would expect it to.  

So, go to this URL:

http://demo.openlinksw.com/sparql

And enter this in the query field:

PREFIX bf:   <http://bibframe.org/vocab/>
SELECT ?subject ?label
WHERE { 
   ?subject bf:providerName ?bnode .
   ?bnode bf:label ?label . 
}

Click "Run Query."  You'll get a handful of results, all coming from pre-loaded BF data.  The column with values like "nodeID://b25764024" are blank nodes.

Lest one believes this to be an oddity of openlink's software, copy this query (same pattern as the above on, just different variable names and properties):

SELECT  ?o ?l
WHERE
  { 
     ?s <http://zbw.eu/namespaces/zbw-extensions/useInsteadNote> ?o .
     ?o <http://www.w3.org/1999/02/22-rdf-syntax-ns#value> ?l
     FILTER (isBlank(?o))
  }
LIMIT   100

(I added that FILTER line just to make sure we get nothing but blank nodes.)

Then, go to this website (which is the SPARQL endpoint for STW Thesaurus for Economics)

http://zbw.eu/beta/sparql/stw.html

Replace the content in the text field with the query above and click "get results."

The column with values like "_:b4" are blank nodes.

All of this is to say that when you say things like "This search does not work on triples with blank nodes" I find that it in fact does.

Yours,
Kevin


-----Original Message-----
From: Bibliographic Framework Transition Initiative Forum
[mailto:[log in to unmask]] On Behalf Of Karen Coyle
Sent: Friday, August 01, 2014 11:15 AM
To: [log in to unmask]
Subject: Re: [BIBFRAME] Blank nodes, xml, ttl was: [BIBFRAME] Proposal to
handle "Providers" differently

Nate,

I agree with what you say below, but I don't think it addresses my concern
which is about the use of blank nodes. Regardless of whether one has a URI
value or a literal value, a node can be named or blank. I know that there is a
tendency to "go blank" when punting on the decision URI/literal, but then
you need to make some other adjustments in your design. As I've already
shown, the use of label in multiple places in the data within blank nodes
makes it very hard to retrieve the desired data:

<http://example.org/1>  a bf:Instance,
      bf:publication [
          a bf:Provider ;
          bf:providerDate "1966" ;
          bf:providerName [ a bf:Organization ; bf:label "Hamlyn" ] ;
          bf:providerPlace [ a bf:Place ; bf:label "London" ]
      ] .

The reason is that you cannot step through blank nodes to select only the
bf:label for either bf:providerName or bf:providerPlace. This search does not
work on triples with blank nodes:

SELECT ?subject ?label
      WHERE { ?subject bf:providerName ?bnode .
                   ?bnode bf:label ?label . }

This could be "solved" by creating specific properties for the labels, such as
bf:providerNameLabel. However, the use of bf:label within blank nodes
simply does not allow retrieval of the desired literals. Or it could be solved by
using named graphs. It does, however, need to be solved.

kc




On 8/1/14, 6:34 AM, Trail, Nate wrote:
Karen,

The current transformation is incomplete in this Provider area, for a couple
of reasons. I think we know we'd like to make          <bf:label>University of
Michigan Press</bf:label> and          <bf:label>Ann Arbor</bf:label> into uris,
but we haven't 'resolved'  where we go to look those things up reliably.
Not all of the "Organizations"   in the MARC data are orgs; they might be
imprints, or statements like "Distributed by Random House", meaning they
are not supposed to be part of  bf:publication, but bf:distribution. etc.
There is no imprint lookup service (yet), especially for historic materials.
Provider places, as has been pointed out, lack jurisdiction, so we're left to
guess that Paris is Paris, France.
Those factors being the case, we're assuming that subsequent passes over
the data will be able to more cleanly parse it and data-ify, and the bf:label
could go away in favor of a uri.
We have a second pass in the works that does lookups to ID.loc.gov for
various controlled vocabulary, and may look up other authoritative sources.
It's not ready for prime time, however.
Nate

-----Original Message-----
From: Bibliographic Framework Transition Initiative Forum
[mailto:[log in to unmask]] On Behalf Of Karen Coyle
Sent: Thursday, July 31, 2014 9:03 PM
To: [log in to unmask]
Subject: [BIBFRAME] Blank nodes, xml, ttl was: [BIBFRAME] Proposal to
handle "Providers" differently
On 7/31/14, 3:30 PM, Ford, Kevin wrote:
Of course, these have the "blank-node-+-label" problem again (still?).
_:xx and _:yy do not need to be blank nodes.  We've been using a lot of
blank nodes in examples, but they do not need to be.

          
Kevin,

You are absolutely right, they do not need to be blank nodes. However, my
discovery of the issue with "bf:label" and blank nodes was on MARC records
that I ran through the BIBFRAME tool [1], not in hand-coded examples.
Obviously, BIBFRAME is not "done" so that tool is an approximation of what
BIBFRAME could be, but there is an unfortunate reliance on blank nodes in its
current state. This fact is somewhat hidden by the use of rdf/xml, and ditto
the email examples in turtle, since blank nodes basically disappear in these
notations. The proof of the pudding is in the triples. Here is a segment of real
BIBFRAME instance data (as transformed from MARC by the BF tool, then
converted to turtle and triples using rapper):
**RDFXML:

<bf:publication>
    <bf:Provider>
      <bf:providerName>
        <bf:Organization>
          <bf:label>University of Michigan Press</bf:label>
        </bf:Organization>
      </bf:providerName>
      <bf:providerPlace>
        <bf:Place>
          <bf:label>Ann Arbor</bf:label>
        </bf:Place>
      </bf:providerPlace>
      <bf:providerDate>1995</bf:providerDate>
    </bf:Provider>
</bf:publication>
</rdf>

**turtle:

      bf:publication [
          bf:providerDate "1995" ;
          bf:providerName [
              bf:label "University of Michigan Press" ;
              a bf:Organization
          ] ;
          bf:providerPlace [
              bf:label "Ann Arbor" ;
              a bf:Place
          ] ;
          a bf:Provider
      ] ;

** triples

<http://bibframe.org/resources/cYO1404049290/3033010>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<http://bibframe.org/vocab/Work> .
<http://bibframe.org/resources/cYO1404049290/3033010>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<http://bibframe.org/vocab/Text> .
_:genid1 <http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<http://bibframe.org/vocab/Provider> .
_:genid2 <http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<http://bibframe.org/vocab/Organization> .
_:genid2 <http://bibframe.org/vocab/label> "University of Michigan
Press" .
_:genid1 <http://bibframe.org/vocab/providerName> _:genid2 .
_:genid3 <http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<http://bibframe.org/vocab/Place> .
_:genid3 <http://bibframe.org/vocab/label> "Ann Arbor" .
_:genid1 <http://bibframe.org/vocab/providerPlace> _:genid3 .
_:genid1 <http://bibframe.org/vocab/providerDate> "1995" .
<http://bibframe.org/resources/cYO1404049290/3033010>
<http://bibframe.org/vocab/publication> _:genid1 .

The blank nodes become much more visible.

Many of the examples that we've seen on these recent threads don't
actually represent "running code," or at least I couldn't transform any
of them using tools that I have. I know this is a discussion, not a
coding session, but I think it would be helpful to do a sanity check
regarding what we are discussing by creating some working examples.
It'll provide a more realistic basis for discussion.

Personally, I'd like to see BIBFRAME move away from the use of blank
nodes wherever possible, and so I'd like to see examples that don't use
them.

kc
[1] http://bibframe.org/tools/transform/start

--
Karen Coyle
[log in to unmask] http://kcoyle.net
m: 1-510-435-8234
skype: kcoylenet

-- 
Karen Coyle
[log in to unmask] http://kcoyle.net
m: 1-510-435-8234
skype: kcoylenet