pymysql模块

先建立远程账户并授权

 grant all on *.* to 'root'@'%'identified by '123';
 flush privileges; 
 # 刷新

mysql模块基本使用

import pymysql

user = input('用户名: ').strip()
pwd = input('密码: ').strip()

conn = pymysql.connect(
   host='192.168.31.80',
   port=3306,
   user='root',
   password='123',
   db='luffy',
   charset='utf8'
)

# 拿到游标
cursor = conn.cursor()

# 执行sql语句
sql = 'select * from userinfo where user="%s" and pwd="%s"' % (user, pwd)
# 不用这招，会导致sql注入问题
rows = cursor.execute(sql)

cursor.close()
conn.close()

# 进行判断

if rows:
   print('登陆成功')
else:
   print('登陆失败')

execute()之sql注入

根本原理：就根据程序的字符串拼接name='%s'，我们输入一个xxx' -- haha,用我们输入的xxx加'在程序中拼接成一个判断条件name='xxx' -- haha'

最后那一个空格，在一条sql语句中如果遇到select * from t1 where id > 3 -- and name='egon';则--之后的条件被注释掉了

#1、sql注入之：用户存在，绕过密码
egon" -- 任意字符

#2、sql注入之：用户不存在，绕过用户与密码
xxx" or 1=1 -- 任意字符

解决方法

import pymysql

user = input('用户名: ').strip()
pwd = input('密码: ').strip()

conn = pymysql.connect(
    host='127.0.0.1',
    port=3306,
    user='root',
    password='123',
    db='luffy',
    charset='utf8'
)

# 拿到游标
cursor = conn.cursor()

# 执行sql语句
sql = 'select * from userinfo where user=%s and pwd=%s' 
# %s 去掉引号，pymysql会自动添加
rows = cursor.execute(sql, [user, pwd])

cursor.close()
conn.close()

# 进行判断

if rows:
    print('登陆成功')
else:
    print('登陆失败')

pymysql增删改

import pymysql

conn = pymysql.connect(
    host='127.0.0.1',
    port=3306,
    user='root',
    password='123',
    db='luffy',
    charset='utf8'
)

# 拿到游标
cursor = conn.cursor()
sql = 'insert into userinfo(user, pwd) values(%s, %s)'
rows = cursor.execute(sql, ('test', '111'))  # 插一条
# rows = cursor.executemany(sql, [('yxx', '123'), ('egon1', '12345')])
# 插多条记录
print(rows)
print(cursor.lastrowid) # 最后一个插入的id

conn.commit()
cursor.close()
conn.close()

sql之查询

import pymysql

# 建立链接
conn=pymysql.connect(
    host='127.0.0.1',
    port=3306,
    user='root',
    password='123',
    db='luffy',
    charset='utf8'
)

# 拿游标
cursor = conn.cursor(pymysql.cursors.DictCursor)  # cursor以字典形式
rows = cursor.execute('select * from userinfo')
# print(rows)
# print(cursor.fetchmany(2))
# res1 = cursor.fetchone()
# res2 = cursor.fetchone()
# res3 = cursor.fetchone()
# res4 = cursor.fetchone()

# print(res1)
# print(res4)
cursor.scroll(3, mode='absolute')  # 相对绝对位置移动
cursor.scroll(3, mode='relative')  # 相对当前位置移动
res5 = cursor.fetchone()
print(res5)
cursor.close()
conn.close()