error in AML

オフライン

HI

Item _cad = inn.newItem("CAD", "get");
Item cad_str = _cad.createRelationship("CAD Structure", "get");
cad_str.setAttribute("where", "CAD_Structure.related_id = '"+this.getProperty("id")+"'");
Item res2 = _cad.apply();

Is there anything wrong?
Res2 is marked as null.