While a simple federated query with http://datos.bne.es/sparql works as expected from the Query Service...
SELECT * WHERE {
SERVICE <http://datos.bne.es/sparql> {
<http://datos.bne.es/resource/XX1719671> ?prop ?value .
}
}... an equivalent one using BIND does not...
SELECT * WHERE {
BIND(<http://datos.bne.es/resource/XX1719671> AS ?id)
SERVICE <http://datos.bne.es/sparql> {
?id ?prop ?value .
}
}... but it does with other data sources like DBpedia...
SELECT * WHERE {
BIND(<http://dbpedia.org/resource/Universe> AS ?id)
SERVICE <http://dbpedia.org/sparql> {
?id ?prop ?value .
}
}I guess this is caused by the fact that http://datos.bne.es/sparql doesn't allow binding. However, if true, this would work if we replaced the corresponding variables with their content in our side.
Federated queries without binding aren't very useful.