About: http://webisa.webdatacommons.org/373733684

Property	Value
http://www.w3.org/1999/02/22-rdf-syntax-ns#type	http://www.w3.org/ns/prov#Entity
http://www.w3.org/ns/prov#value	Querying large sets of related tuples effectively is not really a hard problem as such, it just becomes hard when you try to do it in SQL.In fact, most of the problems you outline are problems related to SQL's built in limitations.
http://www.w3.org/ns/prov#wasQuotedFrom	sqlteam.com