python update数据

#!/usr/bin/env python
# -*- coding:utf-8 -*-
# @Time   : 2017/11/23 23:57
# @Author : lijunjiang
# @File   : update.py
import MySQLdb

select_sql = 'select Grade from Score where Grade < 20'
update_sql = 'update Score set grade = grade + 60 where grade < 50'

def connect_mysql():
    info_mysql = {
        'host': '11.11.11.11',
        'port': 3306,
        'db': 'python',
        # 'charset':'utf8',
        'user': 'python',
        'passwd': 'python'
    }
    try:
        cnx = MySQLdb.connect(**info_mysql)
    except Exception as err:
        raise err
    return cnx
if __name__ == '__main__':
    cnx = connect_mysql()
    try:
        cus = cnx.cursor()
        cus.execute(select_sql)
        result_select = cus.fetchall()
        print(type(result_select))
        print(result_select)
        cus.execute(update_sql)

        cus.execute(select_sql)
        result_select_two = cus.fetchall()
        print(result_select_two)

        cus.close()
    except Exception as err:
        cnx.rollback()
        raise err
    finally:
        cnx.close()