python连接MySQL数据库详解

一.创建数据库test sql语句：create database test
二.创建表trade sql语句：
DROP TABLE IF EXISTS `trade`;

CREATE TABLE `trade` (
`id` int(4) unsigned NOT NULL AUTO_INCREMENT,
`name` varchar(6) NOT NULL COMMENT \'用户真实姓名\',
`account` varchar(11) NOT NULL COMMENT \'银行储蓄账号\',
`saving` decimal(8,2) unsigned NOT NULL DEFAULT \'0.00\' COMMENT \'账户储蓄金额\',
`expend` decimal(8,2) unsigned NOT NULL DEFAULT \'0.00\' COMMENT \'账户支出总计\',
`income` decimal(8,2) unsigned NOT NULL DEFAULT \'0.00\' COMMENT \'账户收入总计\',
PRIMARY KEY (`id`),
UNIQUE KEY `name_UNIQUE` (`name`)
) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=utf8;
INSERT INTO `trade` VALUES (1,\'马化腾\',\'654321\',0.00,0.00,0.00);

三.通过pyMySQL操纵MySQL数据库（pyMySQL下载命令：pip install pymysql）

#!/usr/bin/env python
# -*- coding: utf-8 -*-

import pymysql.cursors

# 连接数据库
connect = pymysql.Connect(
host=\'localhost\',
port=3306,
user=\'root\',
passwd=\'\',
db=\'test\',
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 = (\'马云\', \'123456\', 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, \'123456\')
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 = (\'123456\',)
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（可以先不测这个，观察数据库是否已经添加数据）
# sql = "DELETE FROM trade WHERE account = \'%s\' LIMIT %d"
# data = (\'123456\', 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 = \'654321\' "
sql_2 = "UPDATE trade SET expend = expend + 1000 WHERE account = \'654321\' "
sql_3 = "UPDATE trade SET income = income + 2000 WHERE account = \'654321\' "

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()