\set VERBOSITY terse --------------------------------- Wikidata (Blazegraph) --------------------------------- CREATE SERVER wikidata FOREIGN DATA WRAPPER rdf_fdw OPTIONS (endpoint 'https://query.wikidata.org/sparql', connect_retry '0'); -- IRI description SELECT subject, predicate, object FROM sparql.describe('wikidata', 'DESCRIBE ') ORDER BY object::text COLLATE "C"; subject | predicate | object -----------------------------------------------------------------------------------+------------------------------------------------+------------------------------------------------------------------------------------------------ | | "0"^^ | | "1"^^ | | "2023-12-29T16:06:26Z"^^ | | "2039957927"^^ | | "7"^^ | | "Point(9.083349952 49.46347064)"^^ | | "Straßenwetterstation V550"@de | | "Straßenwetterstation Waldbrunn"@de | | "Straßenwetterstation Waldbrunn"^^ | | "Vom DWD genutzte automatische Wetterstation bei Strümpfelbrunn"@de | | | | | | | | | | | | | | | | | | | | | | | | | | (23 rows) -- graph pattern description SELECT subject, predicate, object FROM sparql.describe('wikidata',' PREFIX wdt: PREFIX wd: DESCRIBE ?s WHERE { ?s wdt:P734 wd:Q59853; wdt:P19 wd:Q84 ; schema:description ?d FILTER(STR(?d) = "British astronomer") }') WHERE predicate = '' AND object = '"Harold Spencer Jones"@en' ORDER BY object::text COLLATE "C"; subject | predicate | object ------------------------------------------+----------------------------------------------+--------------------------- | | "Harold Spencer Jones"@en (1 row) SELECT subject, predicate, object FROM sparql.describe('wikidata', 'DESCRIBE ') WHERE predicate IN ('','') ORDER BY object::text COLLATE "C"; subject | predicate | object --------------------------------------------+----------------------------------------------+--------------------------------------------------------------------- | | "2024-05-01T21:36:41Z"^^ | | "Tuktoyaktuk A"@en | | "Tuktoyaktuk A"@fr (3 rows) SELECT subject, predicate, object FROM sparql.describe( query =>'describe wd:Q471896', server => 'wikidata', base_uri => 'http://test.base.uri/') WHERE predicate = '' ORDER BY object::text COLLATE "C"; subject | predicate | object ------------------------------------------+----------------------------------------------+----------------------------------- | | "A sápadt holdfényben"@hu | | "In fahlem Mondlicht"@de | | "In the Pale Moonlight"@ca | | "In the Pale Moonlight"@en | | "In the Pale Moonlight"@he | | "In the Pale Moonlight"@nl | | "In the Pale Moonlight"@pt | | "In the Pale Moonlight"@sh | | "In the Pale Moonlight"@sv | | "Kuun kalpeassa valossa"@fi | | "La coscienza di un ufficiale"@it (11 rows) -- empty server SELECT * FROM sparql.describe('', 'DESCRIBE '); ERROR: SERVER cannot be empty -- empty DESCRIBE pattern SELECT * FROM sparql.describe('wikidata', ''); ERROR: DESCRIBE pattern cannot be empty -- empty SERVER and DESCRIBE pattern SELECT * FROM sparql.describe('', ''); ERROR: SERVER cannot be empty -- NULL DESCRIBE pattern SELECT * FROM sparql.describe('wikidata', NULL); subject | predicate | object ---------+-----------+-------- (0 rows) -- NULL SERVER SELECT * FROM sparql.describe(NULL, 'DESCRIBE '); subject | predicate | object ---------+-----------+-------- (0 rows) -- NULL SERVER and DESCRIBE pattern SELECT * FROM sparql.describe(NULL, NULL); subject | predicate | object ---------+-----------+-------- (0 rows) -- invalid SERVER SELECT * FROM sparql.describe('invalid', 'DESCRIBE '); ERROR: invalid SERVER: invalid SELECT * FROM sparql.describe(' ', 'DESCRIBE '); ERROR: a SERVER cannot contain only whitespace characters -- invalid DESCRIBE pattern SELECT * FROM sparql.describe('wikidata', 'invalid'); ERROR: invalid DESCRIBE query: invalid SELECT * FROM sparql.describe('wikidata', ' '); ERROR: a DESCRIBE pattern cannot contain only whitespace characters SELECT * FROM sparql.describe('wikidata', 'DESCRIBE http://www.wikidata.org/entity/Q61308849'); -- missing < > ERROR: bad request (HTTP status 400) -- DESCRIBE pattern with a blank node SELECT * FROM sparql.describe('wikidata', '_:bnode1'); ERROR: invalid DESCRIBE query: _:bnode1 SELECT * FROM sparql.describe('wikidata', 'DESCRIBE _:bnode1'); ERROR: bad request (HTTP status 400) -- malformed entity IRI SELECT * FROM sparql.describe('wikidata', 'DESCRIBE '); subject | predicate | object ---------+-----------+-------- (0 rows) -- SELECT query SELECT * FROM sparql.describe('wikidata', 'SELECT ?s ?p ?o WHERE {?s ?p ?o}'); ERROR: invalid DESCRIBE query: SELECT ?s ?p ?o WHERE {?s ?p ?o} DROP SERVER wikidata; ----------------------------------- Virtuoso (DBpedia) ----------------------------------- CREATE SERVER dbpedia FOREIGN DATA WRAPPER rdf_fdw OPTIONS (endpoint 'https://dbpedia.org/sparql'); -- IRI description SELECT subject, predicate, object FROM sparql.describe('dbpedia','dEsCrIBe ') ORDER BY subject::text, object::text COLLATE "C"; subject | predicate | object --------------------------------------------------+----------------------------------------------------+------------------------------------------------------------------------ | | "4"^^ | | "Alien Blood"@en | | "Alien Blood"@en | | "Alien Blood"@en | | "Burton George"@en | | "Captain Leslie T. Peacocke"@en | | "E. D. Horkheimer"@en | | "General Film"@en | | "H. M. Horkheimer"@en | | "Paul Garnett"@en | | "Silent film ..English titles"@en | | "United States"@en | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | (71 rows) DROP SERVER dbpedia;