About: http://webisa.webdatacommons.org/20317158

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	A constraint is a property assigned to a table or column within a table that prevents invalid data values from being entered in the specified column(s).
http://www.w3.org/ns/prov#wasQuotedFrom	articles.org