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Share, discover and reuse the Linked Data has never been easier with a LinkedWiki Platform.

Degrees of Separation and Contact Networks (ala LinkedIn)
Uses Virtuoso SPARQL Extensions to demonstrate degrees of separations and contact network size. This is about demonstrating how to leverage Transitive Relations in a manner that matches what other proprietary Graph Query Languages tend to use as competitive justification against SPARQL.

Reuse these data in your code

Query, endpoint and code for reusing the same data
http://linkeddata.uriburner.com/sparql
PREFIX foaf: <http://xmlns.com/foaf/0.1/> 
SELECT ?o as ?WebID
       ((SELECT COUNT (*) WHERE {?o foaf:knows ?xx})) as ?contact_network_size
       ?dist as ?DegreeOfSeparation 
       <http://www.w3.org/People/Berners-Lee/card#i> as ?knowee
  WHERE
    {
      {
        SELECT ?s ?o
        WHERE
          {
            ?s foaf:knows ?o
          }
      } OPTION (TRANSITIVE, t_distinct, t_in(?s), t_out(?o), t_min (1), t_max (4), t_step ('step_no') as ?dist) .
      FILTER (?s= <http://www.w3.org/People/Berners-Lee/card#i>)
      FILTER (isIRI(?s) and isIRI(?o))
     
    }
  ORDER BY ?dist DESC (?contact_network_size)
  LIMIT 500
Howto write a query SPARQL? (in french)
{{#sparql:PREFIX foaf: <http://xmlns.com/foaf/0.1/> 
SELECT ?o as ?WebID
       ((SELECT COUNT (*) WHERE {?o foaf:knows ?xx})) as ?contact_network_size
       ?dist as ?DegreeOfSeparation 
       <http://www.w3.org/People/Berners-Lee/card#i> as ?knowee
  WHERE
    {
      {
        SELECT ?s ?o
        WHERE
          {
            ?s foaf:knows ?o
          }
      } OPTION (TRANSITIVE, t_distinct, t_in(?s), t_out(?o), t_min (1), t_max (4), t_step ('step_no') as ?dist) .
      FILTER (?s= <http://www.w3.org/People/Berners-Lee/card#i>)
      FILTER (isIRI(?s) and isIRI(?o))
     
    }
  ORDER BY ?dist DESC (?contact_network_size)
  LIMIT 500            
| endpoint = http://linkeddata.uriburner.com/sparql }}
Howto insert this graph in my wiki ?
Test this script in a new tab.
<html>
    <head>
        <script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.4/jquery.min.js"></script>
    </head>
    <body onload="testQuery();">
        <script>
function testQuery(){
    var endpoint = "http://linkeddata.uriburner.com/sparql";
    var query = "PREFIX foaf: <http://xmlns.com/foaf/0.1/>\n\
SELECT ?o as ?WebID\n\
((SELECT COUNT (*) WHERE {?o foaf:knows ?xx})) as ?contact_network_size\n\
?dist as ?DegreeOfSeparation\n\
<http://www.w3.org/People/Berners-Lee/card#i> as ?knowee\n\
WHERE\n\
{\n\
{\n\
SELECT ?s ?o\n\
WHERE\n\
{\n\
?s foaf:knows ?o\n\
}\n\
} OPTION (TRANSITIVE, t_distinct, t_in(?s), t_out(?o), t_min (1), t_max (4), t_step (\'step_no\') as ?dist) .\n\
FILTER (?s= <http://www.w3.org/People/Berners-Lee/card#i>)\n\
FILTER (isIRI(?s) and isIRI(?o))\n\
}\n\
ORDER BY ?dist DESC (?contact_network_size)\n\
LIMIT 500"

   // $('#bodyContentResearch').append(queryDataset);
    $.ajax({
                url: endpoint,
                dataType: 'json', 
                data: { 
                    queryLn: 'SPARQL',
                    query: query , 
                    limit: 'none',
                    infer: 'true',
                    Accept: 'application/sparql-results+json'
                },
                success: displayResult, 
                error: displayError
        });
}

function displayError(xhr, textStatus, errorThrown) {
    console.log(textStatus);
    console.log(errorThrown);
}

function displayResult(data) {
    $.each(data.results.bindings, function(index, bs) {
        console.log(bs);
        $("body").append(JSON.stringify(bs) + "<hr/>");
    });
}

        </script>
    </body>    
</html>
</pre>
  
Test this script in a new tab.
Howto insert this graph in my html page?
<html>
    <head>
        <script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.4/jquery.min.js"></script>
        <script type="text/javascript" src="https://www.google.com/jsapi"></script>
        <script type="text/javascript" src="js/sgvizler/sgvizler.js"></script>
    </head>
<body style="margin:0;">
<div id="sgvzl_example_query" 
   data-sgvizler-endpoint="http://linkeddata.uriburner.com/sparql" 
   data-sgvizler-query="PREFIX foaf: &lt;http://xmlns.com/foaf/0.1/&gt; 
SELECT ?o as ?WebID
       ((SELECT COUNT (*) WHERE {?o foaf:knows ?xx})) as ?contact_network_size
       ?dist as ?DegreeOfSeparation 
       &lt;http://www.w3.org/People/Berners-Lee/card#i&gt; as ?knowee
  WHERE
    {
      {
        SELECT ?s ?o
        WHERE
          {
            ?s foaf:knows ?o
          }
      } OPTION (TRANSITIVE, t_distinct, t_in(?s), t_out(?o), t_min (1), t_max (4), t_step (&#039;step_no&#039;) as ?dist) .
      FILTER (?s= &lt;http://www.w3.org/People/Berners-Lee/card#i&gt;)
      FILTER (isIRI(?s) and isIRI(?o))
     
    }
  ORDER BY ?dist DESC (?contact_network_size)
  LIMIT 500" 
    data-sgvizler-chart='google.visualization.Table'             
    data-sgvizler-chart-options=''  
    data-sgvizler-endpoint_output_format='json'
    data-sgvizler-loglevel='2'   
    style='width:100%; height:450px;'  />



<script>
$(document).ready(function() { 
    sgvizler.containerDrawAll();   
    
});
</script>

</body>
</html>
from SPARQLWrapper import SPARQLWrapper, JSON

sparql = SPARQLWrapper("http://linkeddata.uriburner.com/sparql")
sparql.setQuery("""
    PREFIX foaf: <http://xmlns.com/foaf/0.1/> 
SELECT ?o as ?WebID
       ((SELECT COUNT (*) WHERE {?o foaf:knows ?xx})) as ?contact_network_size
       ?dist as ?DegreeOfSeparation 
       <http://www.w3.org/People/Berners-Lee/card#i> as ?knowee
  WHERE
    {
      {
        SELECT ?s ?o
        WHERE
          {
            ?s foaf:knows ?o
          }
      } OPTION (TRANSITIVE, t_distinct, t_in(?s), t_out(?o), t_min (1), t_max (4), t_step ('step_no') as ?dist) .
      FILTER (?s= <http://www.w3.org/People/Berners-Lee/card#i>)
      FILTER (isIRI(?s) and isIRI(?o))
     
    }
  ORDER BY ?dist DESC (?contact_network_size)
  LIMIT 500""")
sparql.setReturnFormat(JSON)
results = sparql.query().convert()

for result in results["results"]["bindings"]:
    print(result)
    #print(result["label"]["value"])
Howto use SPARQL with Python ?
library(SPARQL) # SPARQL querying package
library(ggplot2)
 
# Step 1 - Set up preliminaries and define query
# Define the data.gov endpoint
endpoint <- "http://linkeddata.uriburner.com/sparql"
# create query statement
query <- "PREFIX foaf: <http://xmlns.com/foaf/0.1/> 
SELECT ?o as ?WebID
       ((SELECT COUNT (*) WHERE {?o foaf:knows ?xx})) as ?contact_network_size
       ?dist as ?DegreeOfSeparation 
       <http://www.w3.org/People/Berners-Lee/card#i> as ?knowee
  WHERE
    {
      {
        SELECT ?s ?o
        WHERE
          {
            ?s foaf:knows ?o
          }
      } OPTION (TRANSITIVE, t_distinct, t_in(?s), t_out(?o), t_min (1), t_max (4), t_step ('step_no') as ?dist) .
      FILTER (?s= <http://www.w3.org/People/Berners-Lee/card#i>)
      FILTER (isIRI(?s) and isIRI(?o))
     
    }
  ORDER BY ?dist DESC (?contact_network_size)
  LIMIT 500" 
# Step 2 - Use SPARQL package to submit query and save results to a data frame
qd <- SPARQL(endpoint,query)
df <- qd$results
SPARQL with R in less than 5 minutes
#!/usr/bin/env ruby
#
# Install sparql for Ruby
#   gem update --system
#   gem install sparql
#
require 'sparql/client'

endpoint = "http://linkeddata.uriburner.com/sparql"
sparql = <<-EOT
PREFIX foaf: <http://xmlns.com/foaf/0.1/> 
SELECT ?o as ?WebID
       ((SELECT COUNT (*) WHERE {?o foaf:knows ?xx})) as ?contact_network_size
       ?dist as ?DegreeOfSeparation 
       <http://www.w3.org/People/Berners-Lee/card#i> as ?knowee
  WHERE
    {
      {
        SELECT ?s ?o
        WHERE
          {
            ?s foaf:knows ?o
          }
      } OPTION (TRANSITIVE, t_distinct, t_in(?s), t_out(?o), t_min (1), t_max (4), t_step ('step_no') as ?dist) .
      FILTER (?s= <http://www.w3.org/People/Berners-Lee/card#i>)
      FILTER (isIRI(?s) and isIRI(?o))
     
    }
  ORDER BY ?dist DESC (?contact_network_size)
  LIMIT 500
EOT

#For Wikidata, the method get is required
#For other SPARQL endpoints, the method post is prefered
client = SPARQL::Client.new(endpoint, :method => :get)
rows = client.query(sparql)

puts "Number of rows: #{rows.size}"
for row in rows
  for key,val in row do
    # print "#{key.to_s.ljust(10)}: #{val}\t"
    print "#{key}: #{val}\t"
  end
  print "\n"
end
Doc Ruby for SPARQL 1.1
endpoint = 'http://linkeddata.uriburner.com/sparql';

query = ['PREFIX foaf: <http://xmlns.com/foaf/0.1/>  '...
'SELECT ?o as ?WebID '...
'       ((SELECT COUNT (*) WHERE {?o foaf:knows ?xx})) as ?contact_network_size '...
'       ?dist as ?DegreeOfSeparation  '...
'       <http://www.w3.org/People/Berners-Lee/card#i> as ?knowee '...
'  WHERE '...
'    { '...
'      { '...
'        SELECT ?s ?o '...
'        WHERE '...
'          { '...
'            ?s foaf:knows ?o '...
'          } '...
'      } OPTION (TRANSITIVE, t_distinct, t_in(?s), t_out(?o), t_min (1), t_max (4), t_step ('step_no') as ?dist) . '...
'      FILTER (?s= <http://www.w3.org/People/Berners-Lee/card#i>) '...
'      FILTER (isIRI(?s) and isIRI(?o)) '...
'      '...
'    } '...
'  ORDER BY ?dist DESC (?contact_network_size) '...
'  LIMIT 500 '];

url_head = strcat(endpoint,'?query=');
url_query = urlencode(query);
format = 'text/tab-separated-values';
url_tail = strcat('&format=', format);

url = strcat(url_head, url_query, url_tail);

% get the data from the endpoint
query_results = urlread(url);

% write the data to a file so that tdfread can parse it
fid = fopen('query_results.txt','w');
if fid>=0
    fprintf(fid, '%s\n', query_results)
    fclose(fid)
end

% this reads the tsv file into a struct
sparql_data = tdfread('query_results.txt')
Project Github MatlabSPARQL
<?php 
require_once('lib/SPARQL/Endpoint.php');

$endpoint ="http://linkeddata.uriburner.com/sparql";
$sp_readonly = new Endpoint($endpoint);
$q = <<<EOD
PREFIX foaf: <http://xmlns.com/foaf/0.1/> 
SELECT ?o as ?WebID
       ((SELECT COUNT (*) WHERE {?o foaf:knows ?xx})) as ?contact_network_size
       ?dist as ?DegreeOfSeparation 
       <http://www.w3.org/People/Berners-Lee/card#i> as ?knowee
  WHERE
    {
      {
        SELECT ?s ?o
        WHERE
          {
            ?s foaf:knows ?o
          }
      } OPTION (TRANSITIVE, t_distinct, t_in(?s), t_out(?o), t_min (1), t_max (4), t_step ('step_no') as ?dist) .
      FILTER (?s= <http://www.w3.org/People/Berners-Lee/card#i>)
      FILTER (isIRI(?s) and isIRI(?o))
     
    }
  ORDER BY ?dist DESC (?contact_network_size)
  LIMIT 500EOD;
$rows = $sp_readonly->query($q, 'rows');
$err = $sp_readonly->getErrors();
if ($err) {
      print_r($err);
      throw new Exception(print_r($err,true));
}

foreach($rows["result"]["variables"] as $variable){
        printf("%-20.20s",$variable);
        echo '|';
 }
 echo "\n";

foreach ($rows["result"]["rows"] as $row){
        foreach($rows["result"]["variables"] as $variable){
                printf("%-20.20s",$row[$variable]);
        echo '|';
        }
        echo "\n";
 }
 ?>
Project Github BorderCloud/SPARQL
import com.bordercloud.sparql.Endpoint;
import java.util.ArrayList;
import java.util.HashMap;

public class Main {

    public static void main(String[] args) {
        try {
            Endpoint sp = new Endpoint("http://linkeddata.uriburner.com/sparql";, false);

            String querySelect = 'PREFIX foaf: <http://xmlns.com/foaf/0.1/>  \n'
                    + 'SELECT ?o as ?WebID \n'
                    + '       ((SELECT COUNT (*) WHERE {?o foaf:knows ?xx})) as ?contact_network_size \n'
                    + '       ?dist as ?DegreeOfSeparation  \n'
                    + '       <http://www.w3.org/People/Berners-Lee/card#i> as ?knowee \n'
                    + '  WHERE \n'
                    + '    { \n'
                    + '      { \n'
                    + '        SELECT ?s ?o \n'
                    + '        WHERE \n'
                    + '          { \n'
                    + '            ?s foaf:knows ?o \n'
                    + '          } \n'
                    + '      } OPTION (TRANSITIVE, t_distinct, t_in(?s), t_out(?o), t_min (1), t_max (4), t_step ('step_no') as ?dist) . \n'
                    + '      FILTER (?s= <http://www.w3.org/People/Berners-Lee/card#i>) \n'
                    + '      FILTER (isIRI(?s) and isIRI(?o)) \n'
                    + '      \n'
                    + '    } \n'
                    + '  ORDER BY ?dist DESC (?contact_network_size) \n'
                    + '  LIMIT 500 \n';

            HashMap rs = sp.query(querySelect);
            printResult(rs,30);

        }catch(EndpointException eex) {
            System.out.println(eex);
            eex.printStackTrace();
        }
    }

    public static void printResult(HashMap rs , int size) {

      for (String variable : (ArrayList) rs.get("result").get("variables")) {
        System.out.print(String.format("%-"+size+"."+size+"s", variable ) + " | ");
      }
      System.out.print("\n");
      for (HashMap value : (ArrayList>) rs.get("result").get("rows")) {
        //System.out.print(value);
        /* for (String key : value.keySet()) {
         System.out.println(value.get(key));
         }*/
        for (String variable : (ArrayList) rs.get("result").get("variables")) {
          //System.out.println(value.get(variable));
          System.out.print(String.format("%-"+size+"."+size+"s", value.get(variable)) + " | ");
        }
        System.out.print("\n");
      }
    }
}
Project Github BorderCloud/SPARQL-JAVA