sparql

pig build pkg pgsparql         # 构建 RPM / DEB 包

pig repo add pgsql -u          # 添加仓库并更新缓存

CREATE EXTENSION sparql CASCADE;  -- 依赖: plperl, plperlu

SELECT * FROM sparql.get_properties('dbpedia', 'http://dbpedia.org/resource/Johann_Sebastian_Bach');

SELECT * FROM sparql.get_references('dbpedia', 'http://dbpedia.org/resource/Johann_Sebastian_Bach');

SELECT sparql.compile_query(endpoint, identifier, sparql_query [, grouping]);

SELECT sparql.compile_query('dbpedia', 'ludwig_van', $$
  SELECT ?predicate, ?object
  WHERE {
    <http://dbpedia.org/resource/Ludwig_van_Beethoven> ?predicate ?object.
  }
$$, '{predicate}');

-- 现在可以通过创建的视图进行查询
SELECT * FROM ludwig_van;