About: http://webisa.webdatacommons.org/177952209

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 that is assigned to a column or a group of columns to prevent incorrect or corrupt data from entering into the tables.
http://www.w3.org/ns/prov#wasQuotedFrom	techmixing.com