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    • VOS.VirtTipsAndTricksCustomControlLabelsURI(Last) -- Owiki? , 2018-04-13 12:08:46 Edit
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    owiki 2018-04-13 12:08:46

    Custom Controlling Virtuoso Labels for URI functionality

    What is this?

    A component of Virtuoso's DBMS hosted faceted browser engine for Linked Data that enhances UI by automagically relegating URIs to the @href attributes of an HTML anchor while using label property values for actual anchor text.

    Why is this important?

    The fundamental UI/UX goal of Linked Data oriented client solutions should always be to make URIs invisible without compromising their inherent power re. Web experience e.g., the ability to drill-down from an position on the WWW graph using click (de-reference) based follow-your-nose patterns.

    URIs lie at the very core of that makes the Web and its Linked Data dimension tick. Unfortunately, they are also distracting to most end-users thereby compromising UI aesthetics.

    How do I use this functionality?

    First, lets understand the fundamental challenge. There are a number of annotation oriented attributes (or predicates) used in relations across databases, data spaces, and stores the exposed access to Linked Data. Unfortunately, there isn't a universally adopted attribute/predicate for 'labels', since everyone doesn't uniformly use rdfs:label when constructing Linked Data.

    Virtuoso solves the problem at hand by enabling you to populate a named graph with rdfs:subPropertyOf and owl:equivalentProperty relations (triples) that map disparate annotation properties to Virtuoso's in-built virtrdf:label annotation property. Once in place, the aforementioned named graph is then used as the basis for an inference rule that's optionally available for use via SPARQL and/or the Faceted Browser.

    Example

    This is example is focuses on the in-built 'facets' named graph that is used by faceted browser engine.

    Prerequisites

    Make sure the following packages are installed:

    Basic Steps

    1. Load for ex. http://www.w3.org/People/Berners-Lee/card by accessing: 

      http://localhost:8890/about/html/http://www.w3.org/People/Berners-Lee/card





    2. View http://cname/describe/?url=http://www.w3.org/People/Berners-Lee/card%23i, so for ex.: 

      http://localhost:8890/describe/?url=http://www.w3.org/People/Berners-Lee/card%23i

    3. As result the "About" value will be shown as URI: 

      http://www.w3.org/People/Berners-Lee/card#i





    4. Next use SPARQL 1.1 Update Statement to populate the 'facets' named graph: 

      SPARQL INSERT INTO GRAPH <facets> 
  {
    <http://www.w3.org/2000/01/rdf-schema#label>  rdfs:subPropertyOf  virtrdf:label  .
    <http://purl.org/dc/elements/1.1/title>       rdfs:subPropertyOf  virtrdf:label  .
    <http://xmlns.com/foaf/0.1/name>              rdfs:subPropertyOf  virtrdf:label  .
    <http://xmlns.com/foaf/0.1/nick>              rdfs:subPropertyOf  virtrdf:label  .
    <http://www.geonames.org/ontology#name>       rdfs:subPropertyOf  virtrdf:label  .
  }
;

Query result:

callret-0
ANY
 Insert into <facets>, 5 (or less) triples -- done
No. of rows in result: 1

    5. Use the named graph above as the basis for an inference rule or simply issue this command whenever you've added new relations to the 'facets' named graph: 

      rdfs_rule_set ('facets', 'facets');

      • Note: In situations where you have alternative named graphs (e.g. 'virtrdf-label') which the relations you seek in an alternative named graph, you can bring those to bear by issuing the following command: 

        rdfs_rule_set('facets','virtrdf-label');

    6. View again http://cname/describe/?url=http://www.w3.org/People/Berners-Lee/card%23i, so for ex.: 

      http://localhost:8890/describe/?url=http://www.w3.org/People/Berners-Lee/card%23i

    7. As result the "About" value will be shown as label: 

      TimBL





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