simply updates all rows and sets COL to NEW_VAL where col = old_val
        e.g. update_old_to_new("NAME", "The University of Adelaide", "University of Adelaide")
        will generate
        UPDATE table op SET op.NAME = 'University of Adelaide' WHERE op.NAME = 'The University of Adelaide';

def update_old_to_new(self, col, old_val, new_val):
        """ simply updates all rows and sets COL to NEW_VAL where col = old_val
        e.g. update_old_to_new("NAME", "The University of Adelaide", "University of Adelaide")
        will generate
        UPDATE table op SET op.NAME = 'University of Adelaide' WHERE op.NAME = 'The University of Adelaide';
        """
        self.sql_text += "UPDATE " + self.fact_table + " SET " + col + " = '" + new_val + "' WHERE " + col + " = '" + old_val + "'; \n"