code: def update_old_to_new(self, col, old_val, new_val):
          
          self.sql_text += "UPDATE " + self.fact_table + " SET " + col + " = '" + new_val + "' WHERE " + col + " = '" + old_val + "'; \n"
docs: 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';