QueryBuilderService

service in module sparql

Methods

• buildQuery(queryTemplate, resultSet, [orderBy])

  Build a pageable SPARQL query.

  Parameters

  Param	Type	Details
  queryTemplate	string	The SPARQL query with <RESULT_SET> as a placeholder for the result set query, which is a subquery that returns the distinct URIs of all the resources to be paged. The resource URIs are assumed to bind to the variable ?id.
  resultSet	string	Constraints that result in the URIs of the resources to page. The URIs should be bound as ?id.
  [orderBy]	string	A SPARQL expression that can be used to order the results. Default is '?id'.

  Returns

  Object

  a query object with the following properties: query - {string} - The constructed SPARQL queryTemplate (with a <PAGE> placeholder for paging). resultSetQry - {string} - The result set query.

  Example

  var resultSet = '?id a <http://dbpedia.org/ontology/Writer> .';
  
  var queryTemplate =
  'SELECT * WHERE { ' +
  ' <RESULT_SET> ' +
  ' OPTIONAL { ?id rdfs:label ?label . } ' +
  '}';
  
  var qryObj = queryBuilder.buildQuery(qry, resultSet, '?id');
  
  // qryObj.query returns (without line breaks):
  // PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
  // PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
  // SELECT * WHERE {
  //   {
  //     SELECT DISTINCT ?id {
  //       ?id a <http://dbpedia.org/ontology/Writer>.
  //     } ORDER BY ?id <PAGE>
  //   }
  //   OPTIONAL { ?id rdfs:label ?label . }
  // }
  
  // qryObj.resultSetQry returns (without line breaks):
  // PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
  // PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
  // SELECT DISTINCT ?id {
  //   ?id a <http://dbpedia.org/ontology/Writer>.
  // } ORDER BY ?id <PAGE>