python连接mysql处理数据pymysql模块的使用

import pymysql
import re

sql = 'select * from st'
conn = pymysql.connect(host="128.0.0.1", user="root", passwd="password", db="st",charset='utf8')
cur = conn.cursor()
try:
cur.execute(sql)
item=cur.fetchall()
new_item={}
for i in item:
new_item[i[0]]=i[1].replace(\n','')
for key,value in new_item.items():
cur.execute('update st set html=%s where id=%s; ', (value,key))

except Exception:
print("faile")
raise
finally:
conn.commit()
cur.close()