python中操做mysql的pymysql模塊詳解

簡述

pymsql是Python中操做MySQL的模塊，其使用方法和MySQLdb幾乎相同。但目前pymysql支持python3.x然後者不支持3.x版本。
本文測試python版本：3.5.2。mysql版本：5.7.18

1、安裝

pip install pymysql

2、使用操做

1. 執行SQL

#!/usr/bin/env python
# _*_ coding:utf-8 _*_
__author__ = 'junxi'

import pymysql

# 建立鏈接
conn = pymysql.connect(host='127.0.0.1', port=3306, user='blog', passwd='123456', db='blog', charset='utf8')

# 建立遊標, 查詢數據默認爲元組類型
cursor = conn.cursor()


# 執行SQL，並返回收影響行數
row1 = cursor.execute("update users set password = '123'")
print(row1)
# 執行SQL，並返回受影響行數
row2 = cursor.execute("update users set password = '456' where id > %s", (1,))
print(row2)
# 執行SQL，並返回受影響行數（使用pymysql的參數化語句防止SQL注入）
row3 = cursor.executemany("insert into users(username, password, email)values(%s, %s, %s)", [("ceshi3", '333', 'ceshi3@11.com'), ("ceshi4", '444', 'ceshi4@qq.com')])
print(row3)

# 提交，否則沒法保存新建或者修改的數據
conn.commit()
# 關閉遊標
cursor.close()
# 關閉鏈接
conn.close()

提示：存在中文的時候，鏈接須要添加charset='utf8'，不然中文顯示亂碼。

二、獲取查詢數據

#!/usr/bin/env python
# _*_ coding:utf-8 _*_
__author__ = 'junxi'

import pymysql

# 建立鏈接
conn = pymysql.connect(host='127.0.0.1', port=3306, user='blog', passwd='123456', db='blog', charset='utf8')

# 建立遊標, 查詢數據默認爲元組類型
cursor = conn.cursor()
cursor.execute("select * from users")

# 獲取第一行數據
row_1 = cursor.fetchone()
print(row_1)
# 獲取前n行數據
row_n = cursor.fetchmany(3)
print(row_n)
# 獲取全部數據
row_3 = cursor.fetchall()
print(row_3)


# 提交，否則沒法保存新建或者修改的數據
conn.commit()
# 關閉遊標
cursor.close()
# 關閉鏈接
conn.close()

三、獲取新建立數據自增ID
能夠獲取到最新自增的ID，也就是最後插入的一條數據ID

#!/usr/bin/env python
# _*_ coding:utf-8 _*_
__author__ = 'junxi'

import pymysql

# 建立鏈接
conn = pymysql.connect(host='127.0.0.1', port=3306, user='blog', passwd='123456', db='blog', charset='utf8')

# 建立遊標, 查詢數據默認爲元組類型
cursor = conn.cursor()

cursor.executemany("insert into users(username, password, email)values(%s, %s, %s)", [("ceshi3", '333', 'ceshi3@11.com'), ("ceshi4", '444', 'ceshi4@qq.com')])
new_id = cursor.lastrowid
print(new_id)


# 提交，否則沒法保存新建或者修改的數據
conn.commit()
# 關閉遊標
cursor.close()
# 關閉鏈接
conn.close()

四、移動遊標

操做都是靠遊標，那對遊標的控制也是必須的

注：在fetch數據時按照順序進行，可使用cursor.scroll(num,mode)來移動遊標位置，如：
 
cursor.scroll(1,mode='relative') # 相對當前位置移動
cursor.scroll(2,mode='absolute') # 相對絕對位置移動

五、fetch數據類型

關於默認獲取的數據是元組類型，若是想要或者字典類型的數據，即：

import pymysql

# 建立鏈接
conn = pymysql.connect(host='127.0.0.1', port=3306, user='blog', passwd='123456', db='blog', charset='utf8')

# 遊標設置爲字典類型
cursor = conn.cursor(cursor=pymysql.cursors.DictCursor)
# 左鏈接查詢
r = cursor.execute("select * from users as u left join articles as a on u.id = a.user_id where a.user_id = 2")
result = cursor.fetchall()
print(result)

# 查詢一個表的全部字段名
c = cursor.execute("SHOW FULL COLUMNS FROM users FROM blog")
cc = cursor.fetchall()


# 提交，否則沒法保存新建或者修改的數據
conn.commit()
# 關閉遊標
cursor.close()
# 關閉鏈接
conn.close()

查看運行結果：

[{'user_id': 2, 'id': 2, 'password': '456', 'email': 'xinlei2017@test.com', 'a.id': 2, 'content': '成名之路', 'title': '星光大道', 'username': 'tangtang'}]

六、調用存儲過程

a、調用無參存儲過程

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

import pymysql
 
conn = pymysql.connect(host='127.0.0.1', port=3306, user='blog', passwd='123456', db='blog', charset='utf8')
#遊標設置爲字典類型
cursor = conn.cursor(cursor=pymysql.cursors.DictCursor)
#無參數存儲過程
cursor.callproc('p2')  #等價於cursor.execute("call p2()")
 
row_1 = cursor.fetchone()
print row_1
 
 
conn.commit()
cursor.close()
conn.close()

b、調用有參存儲過程

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

import pymysql
 
conn = pymysql.connect(host='127.0.0.1', port=3306, user='blog', passwd='123456', db='blog', charset='utf8')
cursor = conn.cursor(cursor=pymysql.cursors.DictCursor)
 
cursor.callproc('p1', args=(1, 22, 3, 4))
#獲取執行完存儲的參數,參數@開頭
cursor.execute("select @p1,@_p1_1,@_p1_2,@_p1_3")  
# {u'@_p1_1': 22, u'@p1': None, u'@_p1_2': 103, u'@_p1_3': 24}
row_1 = cursor.fetchone()
print row_1
 
 
conn.commit()
cursor.close()
conn.close()

3、關於pymysql防注入

一、字符串拼接查詢，形成注入

正常查詢語句：

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

import pymysql
 
conn = pymysql.connect(host='127.0.0.1', port=3306, user='blog', passwd='123456', db='blog', charset='utf8')
cursor = conn.cursor()
username = "ceshi1"
password = "ceshi1passwd"
# 正常構造語句的狀況
sql = "select username, password from users where user='%s' and pass='%s'" % (username, password)
# sql = select username, password from users where user='ceshi1' and pass='ceshi1passwd'
row_count = cursor.execute(sql) 
row_1 = cursor.fetchone()
print row_count, row_1
 
conn.commit()
cursor.close()
conn.close()

構造注入語句：

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

import pymysql
 
conn = pymysql.connect(host='127.0.0.1', port=3306, user='blog', passwd='123456', db='blog', charset='utf8')
cursor = conn.cursor()
 
username = "u1' or '1'-- "
password = "u1pass"
sql="select username, password from users where username='%s' and password='%s'" % (username, password)
 
# 拼接語句被構形成下面這樣，永真條件，此時就注入成功了。所以要避免這種狀況需使用pymysql提供的參數化查詢。
# select user,pass from tb7 where user='u1' or '1'-- ' and pass='u1pass'
 
row_count = cursor.execute(sql)
row_1 = cursor.fetchone()
print row_count,row_1
 
 
conn.commit()
cursor.close()
conn.close()

二、避免注入，使用pymysql提供的參數化語句

正常參數化查詢

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

 
import pymysql
 
conn = pymysql.connect(host='127.0.0.1', port=3306, user='blog', passwd='123456', db='blog', charset='utf8')
cursor = conn.cursor()
username="u1"
password="u1pass"
#執行參數化查詢
row_count=cursor.execute("select username,password from tb7 where username=%s and password=%s",(username,password))
row_1 = cursor.fetchone()
print row_count,row_1
 
conn.commit()
cursor.close()
conn.close()

構造注入，參數化查詢注入失敗。

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

import pymysql
 
conn = pymysql.connect(host='127.0.0.1', port=3306, user='blog', passwd='123456', db='blog', charset='utf8')
cursor = conn.cursor()
 
username="u1' or '1'-- "
password="u1pass"
#執行參數化查詢
row_count=cursor.execute("select username,password from users where username=%s and password=%s",(username,password))
#內部執行參數化生成的SQL語句，對特殊字符進行了加\轉義，避免注入語句生成。
# sql=cursor.mogrify("select username,password from users where username=%s and password=%s",(username,password))
# print sql
#select username,password from users where username='u1\' or \'1\'-- ' and password='u1pass'被轉義的語句。
 
row_1 = cursor.fetchone()
print row_count,row_1
 
conn.commit()
cursor.close()
conn.close()

結論：excute執行SQL語句的時候，必須使用參數化的方式，不然必然產生SQL注入漏洞。

三、使用存mysql儲過程動態執行SQL防注入

使用MYSQL存儲過程自動提供防注入，動態傳入SQL到存儲過程執行語句。
delimiter \\
DROP PROCEDURE IF EXISTS proc_sql \\
CREATE PROCEDURE proc_sql (
  in nid1 INT,
  in nid2 INT,
  in callsql VARCHAR(255)
  )
BEGIN
  set @nid1 = nid1;
  set @nid2 = nid2;
  set @callsql = callsql;
    PREPARE myprod FROM @callsql;
--   PREPARE prod FROM 'select * from users where nid>? and nid<?';  傳入的值爲字符串，？爲佔位符
--   用@p1，和@p2填充佔位符
    EXECUTE myprod USING @nid1,@nid2;
  DEALLOCATE prepare myprod;
 
END\\
delimiter ;
set @nid1=12;
set @nid2=15;
set @callsql = 'select * from users where nid>? and nid<?';
CALL proc_sql(@nid1,@nid2,@callsql)

pymsql中調用

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

import pymysql
 
conn = pymysql.connect(host='127.0.0.1', port=3306, user='blog', passwd='123456', db='blog', charset='utf8')
cursor = conn.cursor()
sql1="select * from users where nid>? and nid<?"
cursor.callproc('proc_sql', args=(11, 15, sql1))
 
rows = cursor.fetchall()
print rows
conn.commit()
cursor.close()
conn.close()

4、使用with簡化鏈接過程

# 使用with簡化鏈接過程，每次都鏈接關閉很麻煩，使用上下文管理，簡化鏈接過程
import pymysql
import contextlib


# 定義上下文管理器，鏈接後自動關閉鏈接
@contextlib.contextmanager
def mysql(host='127.0.0.1', port=3306, user='blog', passwd='123456', db='blog', charset='utf8'):
    conn = pymysql.connect(host=host, port=port, user=user, passwd=passwd, db=db, charset=charset)
    cursor = conn.cursor(cursor=pymysql.cursors.DictCursor)
    try:
        yield cursor
    finally:
        conn.commit()
        cursor.close()
        conn.close()

# 執行sql
with mysql() as cursor:
    # 左鏈接查詢
    r = cursor.execute("select * from users as u left join articles as a on u.id = a.user_id where a.user_id = 2")
    result = cursor.fetchall()
    print(result)

查看運行結果：

[{'title': '星光大道', 'username': 'tangtang', 'user_id': 2, 'email': 'xinlei3166@126.com', 'a.id': 2, 'content': '成名之路', 'password': '456', 'id': 2}]