pymysql

-- 受權加建立mysql帳號一步到位，%表明遠程
grant all on *.* to 'gudon'@'%' identified by '123';
mysql> flush privileges;  -- 使操做結果當即生效
-- 建表
mysql> select * from userinfo;
+----+--------+-------+
| id | user   | pwd   |
+----+--------+-------+
|  1 | gudon  | 123   |
|  2 | Astro  | 1234  |
|  3 | Nurato | 12345 |
+----+--------+-------+

# pip3 install pymysql
import pymysql

user = input('user>>').strip()
pwd = input('pwd>>').strip()


# 建鏈接
conn = pymysql.connect(
    host='127.0.0.1',
    port=3306,
    user='gudon',
    password='123',
    db='db9',
    charset='utf8'
)

# 拿到遊標
cursor = conn.cursor()

# 執行sql
sql = 'select * from userinfo where user = "%s" and pwd = "%s"' %(user, pwd)

rows = cursor.execute(sql)

cursor.close()
conn.close()

# 進行判斷
if rows:
    print('登陸成功')
else:
    print('登陸失敗')
    
-------------------結果----------------------
user>>gudon
pwd>>123
登陸成功

​

sql注入：

user>>gudon "-- xxxx
pwd>>
登陸成功

-- 此時sql 爲 
select * from userinfo where user = "gudon "-- xxxx" and pwd = ""
後面的條件被註釋掉了


user>>xxx" or 1=1 -- xxx
pwd>>
登陸成功
實際執行的sql爲 select * from userinfo where user = "xxx" or 1=1 -- xxx" and pwd = ""

sql注入解決辦法：

# 執行sql
sql = 'select * from userinfo where user=%s and pwd=%s'
rows = cursor.execute(sql, (user, pwd))

​

​

2 增刪改查

(1)增刪改

import pymysql

# 建鏈接
conn = pymysql.connect(
    host='127.0.0.1',
    port=3306,
    user='gudon',
    password='123',
    db='db9',
    charset='utf8'
)
# 拿遊標
cursor = conn.cursor()
# 執行sql
# 增、刪、改
sql = 'insert into userinfo(user,pwd) values (%s,%s)'

# 插入單條數據
# rows = cursor.execute(sql,('jack','123'))
# print(rows)

# 插入多條數據
rows = cursor.executemany(sql,[('gd01','123'),('gd02','123'),('zs','123')])
print(rows)
conn.commit()  # commit 後纔會真正更改數據庫中的數據

# 關閉
cursor.close()
conn.close()

​

(2) 查

import pymysql

# 建鏈接
conn = pymysql.connect(
    host='127.0.0.1',
    port=3306,
    user='gudon',
    password='123',
    db='db9',
    charset='utf8'
)
# 拿遊標
# cursor = conn.cursor()
cursor = conn.cursor(pymysql.cursors.DictCursor) # 使查詢結果爲字典格式

# 執行sql
# 查
sql = 'select * from userinfo'

# 插入單條數據
rows = cursor.execute(sql)  # 返回查詢條數

# print(cursor.fetchone())  # (1, 'gudon', '123')
# print(cursor.fetchone())  # (2, 'Astro', '1234')
# 取到最後一個沒有數據了，則返回None

print(cursor.fetchmany(2))  # 指定取出條數
# [{'id': 1, 'user': 'gudon', 'pwd': '123'}, {'id': 2, 'user': 'Astro', 'pwd': '1234'}]

# print(cursor.fetchall())  # 取出全部


# cursor.scroll(3,mode='absolute') # 相對絕對位置移動，從0開始數3個，下次取第4條
# cursor.scroll(3,mode='relative') # 相對當前位置移動 ，相對於遊標目前的位置，日後數3個


# 關閉
cursor.close()
conn.close()