About: http://webisa.webdatacommons.org/396182828

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	After some research, my options appear to be the use of either: ON DUPLICATE KEY UPDATE which implies an unnecessary update at some cost, or INSERT IGNORE which implies an invitation for other kinds of failure to slip in unannounced.
http://www.w3.org/ns/prov#wasQuotedFrom	stackoverflow.com