_:vb50780121	<http://www.w3.org/ns/r2rml#constant>	<http://demo.openlinksw.com/schemas/aml/lastName> .
_:vb50780122	<http://www.w3.org/ns/r2rml#predicateMap>	_:vb50780121 .
_:vb50780123	<http://www.w3.org/ns/r2rml#column>	"last_name" .
_:vb50780122	<http://www.w3.org/ns/r2rml#objectMap>	_:vb50780123 .