About: http://webisa.webdatacommons.org/11852256

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	update the database, catch it at the form/program and yell at the user If you are the programmer, and no one will EVER update the database except through your code, then you can enforce the no NULLs" at the code level.
http://www.w3.org/ns/prov#wasQuotedFrom	ittoolbox.com