About: http://webisa.webdatacommons.org/384226546

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	The answer is a combination of the null bitmap in the record, plus the metadata for the table/index stored in the system tables.
http://www.w3.org/ns/prov#wasQuotedFrom	sqlskills.com