pymysql.Connect()参数说明
host(str): MySQL服务器地址
port(int): MySQL服务器端口号
user(str): 用户名
passwd(str): 密码
db(str): 数据库名称
charset(str): 连接编码

connection对象支持的方法
cursor() 使用该连接创建并返回游标
commit() 提交当前事务
rollback() 回滚当前事务
close() 关闭连接

cursor对象支持的方法
execute(op) 执行一个数据库的查询命令
fetchone() 取得结果集的下一行
fetchmany(size) 获取结果集的下几行
fetchall() 获取结果集中的所有行
rowcount() 返回数据条数或影响行数
close() 关闭游标对象

import pymysql.cursors

连接数据库

connect = pymysql.Connect(
host=‘localhost’,
port=3310,
user=‘woider’,
passwd=‘3243’,
db=‘python’,
charset=‘utf8’
)

获取游标

cursor = connect.cursor()

插入数据

sql = “INSERT INTO trade (name, account, saving) VALUES ( ‘%s’, ‘%s’, %.2f )”
data = (‘雷军’, ‘13512345678’, 10000)
cursor.execute(sql % data)
connect.commit()
print(‘成功插入’, cursor.rowcount, ‘条数据’)

修改数据

sql = "UPDATE trade SET saving = %.2f WHERE account = ‘%s’ "
data = (8888, ‘13512345678’)
cursor.execute(sql % data)
connect.commit()
print(‘成功修改’, cursor.rowcount, ‘条数据’)

查询数据

sql = "SELECT name,saving FROM trade WHERE account = ‘%s’ "
data = (‘13512345678’,)
cursor.execute(sql % data)
for row in cursor.fetchall():
print(“Name:%s\tSaving:%.2f” % row)
print(‘共查找出’, cursor.rowcount, ‘条数据’)

删除数据

sql = “DELETE FROM trade WHERE account = ‘%s’ LIMIT %d”
data = (‘13512345678’, 1)
cursor.execute(sql % data)
connect.commit()
print(‘成功删除’, cursor.rowcount, ‘条数据’)

事务处理

sql_1 = "UPDATE trade SET saving = saving + 1000 WHERE account = ‘18012345678’ "
sql_2 = "UPDATE trade SET expend = expend + 1000 WHERE account = ‘18012345678’ "
sql_3 = "UPDATE trade SET income = income + 2000 WHERE account = ‘18012345678’ "

try:
cursor.execute(sql_1) # 储蓄增加1000
cursor.execute(sql_2) # 支出增加1000
cursor.execute(sql_3) # 收入增加2000
except Exception as e:
connect.rollback() # 事务回滚
print(‘事务处理失败’, e)
else:
connect.commit() # 事务提交
print(‘事务处理成功’, cursor.rowcount)

关闭连接

cursor.close()
connect.close()