prefix entest: <http://ont.enapso.com/test#>
prefix xsd: <http://www.w3.org/2001/XMLSchema#>

with <http://ont.enapso.com/test>
delete {
    entest:Person_AlexanderSchulze entest:firstName ?o
}
insert {
    entest:Person_AlexanderSchulze entest:firstName "123456"^^xsd:int
}
where {
    entest:Person_AlexanderSchulze entest:firstName ?o 
}