AdvancedSparqlService

service in module sparql

Methods

• getObjects(sparqlQry, [pageSize], [resultSetQry], [pagesPerQuery])

  Get the SPARQL query results as a list of objects as mapped by the mapper given at init. Results are paged using PagerService if pageSize is given. This uses the makeObjectList method of the mapper.

  Parameters

  Param	Type	Details
  sparqlQry	string	The SPARQL query.
  [pageSize]	number	The page size.
  [resultSetQry]	string	The query that defines the result set of the query (sparqlQry). I.e. a sub query that returns the distinct URIs of all the resources to be paged. Required if pageSize is given, i.e. when results should be paged.
  [pagesPerQuery]	number	The number of pages to get per query.

  Returns

  promise

  A promise of the list of the query results as objects, or if pageSize was gicen, a promise of a PagerService instance.

  Example

  var prefixes =
  'PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> ' +
  'PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#> ';
  
  // Note the `<PAGE>` placeholder
  var resultSet =
  ' { ' +
  '   SELECT DISTINCT ?id { ' +
  '     ?id a <http://dbpedia.org/ontology/Writer> . ' +
  '   } ORDER BY ?id <PAGE> ' +
  ' } ';
  
  var qry = prefixes +
  'SELECT * WHERE { ' +
    resultSet +
  ' OPTIONAL { ?id rdfs:label ?label . } ' +
  '}';
  
  var resultSetQry = prefixes + resultSet;
  var resultPromise = endpoint.getObjects(qry, 10, resultSetQry, 1);
  
  // Or you can use the `QueryBuilderService` for convenience:
  
  var resultSet = '?id a <http://dbpedia.org/ontology/Writer> .';
  
  var queryTemplate =
  'SELECT * WHERE { ' +
  ' <RESULT_SET ' +
  ' OPTIONAL { ?id rdfs:label ?label . } ' +
  '}';
  
  var queryBuilder = new QueryBuilderService(prefixes);
  var qryObj = queryBuilder.buildQuery(qry, resultSet, '?id');
  
  var resultPromise = endpoint.getObjects(qryObj.query, 10, qryObj.resultSetQry, 1);
  

• getObjectsNoGrouping(sparqlQry, [pageSize], [pagesPerQuery])

  Get the SPARQL query results as a list of objects. Results are paged if pageSize is given. This uses the makeObjectListNoGrouping method of the mapper.

  Parameters

  Param	Type	Details
  sparqlQry	string	The SPARQL query.
  [pageSize]	number	The page size.
  [pagesPerQuery]	number	The number of pages to get per query.

  Returns

  promise

  A promise of the list of the query results as objects, or if pageSize was given, a promise of a PagerService instance.

  Example

  var qry =
  'PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#> ';
  'SELECT * WHERE { ' +
  ' ?id a <http://dbpedia.org/ontology/Writer> . ' +
  ' OPTIONAL { ?id rdfs:label ?label . } ' +
  '}';
  
  var resultPromise = endpoint.getObjects(qry, 10, 1);
  
  // Without paging:
  var resultPromise = endpoint.getObjects(qry);