Python中操作mysql的pymysql模块详解

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前言

pymsql是Python中操作MySQL的模块,其使用方法和MySQLdb几乎相同。但目前pymysql支持python3.x而后者不支持3.x版本。

本文测试python版本:2.7.11。mysql版本:5.6.24

一、安装


    pip3 install pymysql

二、使用操作

1、执行SQL


    #!/usr/bin/env pytho
    # -*- coding:utf-8 -*-
    import pymysql

    # 创建连接
    conn = pymysql.connect(host='127.0.0.1', port=3306, user='root', passwd='', db='tkq1', charset='utf8')
    # 创建游标
    cursor = conn.cursor()

    # 执行SQL,并返回收影响行数
    effect_row = cursor.execute("select * from tb7")

    # 执行SQL,并返回受影响行数
    #effect_row = cursor.execute("update tb7 set pass = '123' where nid = %s", (11,))

    # 执行SQL,并返回受影响行数,执行多次
    #effect_row = cursor.executemany("insert into tb7(user,pass,licnese)values(%s,%s,%s)", [("u1","u1pass","11111"),("u2","u2pass","22222")])


    # 提交,不然无法保存新建或者修改的数据
    conn.commit()

    # 关闭游标
    cursor.close()
    # 关闭连接
    conn.close()

注意:存在中文的时候,连接需要添加charset='utf8',否则中文显示乱码。

2、获取查询数据


    #! /usr/bin/env python
    # -*- coding:utf-8 -*-
    # __author__ = "TKQ"
    import pymysql

    conn = pymysql.connect(host='127.0.0.1', port=3306, user='root', passwd='', db='tkq1')
    cursor = conn.cursor()
    cursor.execute("select * from tb7")

    # 获取剩余结果的第一行数据
    row_1 = cursor.fetchone()
    print row_1
    # 获取剩余结果前n行数据
    # row_2 = cursor.fetchmany(3)

    # 获取剩余结果所有数据
    # row_3 = cursor.fetchall()

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

3、获取新创建数据自增ID

可以获取到最新自增的ID,也就是最后插入的一条数据ID


    #! /usr/bin/env python
    # -*- coding:utf-8 -*-
    # __author__ = "TKQ"
    import pymysql

    conn = pymysql.connect(host='127.0.0.1', port=3306, user='root', passwd='', db='tkq1')
    cursor = conn.cursor()
    effect_row = cursor.executemany("insert into tb7(user,pass,licnese)values(%s,%s,%s)", [("u3","u3pass","11113"),("u4","u4pass","22224")])
    conn.commit()
    cursor.close()
    conn.close()
    #获取自增id
    new_id = cursor.lastrowid      
    print new_id

4、移动游标

操作都是靠游标,那对游标的控制也是必须的


    注:在fetch数据时按照顺序进行,可以使用cursor.scroll(num,mode)来移动游标位置,如:

    cursor.scroll(1,mode='relative') # 相对当前位置移动
    cursor.scroll(2,mode='absolute') # 相对绝对位置移动

5、fetch数据类型

关于默认获取的数据是元祖类型,如果想要或者字典类型的数据,即:


    #! /usr/bin/env python
    # -*- coding:utf-8 -*-
    # __author__ = "TKQ"
    import pymysql

    conn = pymysql.connect(host='127.0.0.1', port=3306, user='root', passwd='', db='tkq1')
    #游标设置为字典类型
    cursor = conn.cursor(cursor=pymysql.cursors.DictCursor)
    cursor.execute("select * from tb7")

    row_1 = cursor.fetchone()
    print row_1  #{u'licnese': 213, u'user': '123', u'nid': 10, u'pass': '213'}

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

6、调用存储过程

a、调用无参存储过程


    #! /usr/bin/env python
    # -*- coding:utf-8 -*-
    # __author__ = "TKQ"

    import pymysql

    conn = pymysql.connect(host='127.0.0.1', port=3306, user='root', passwd='', db='tkq1')
    #游标设置为字典类型
    cursor = conn.cursor(cursor=pymysql.cursors.DictCursor)
    #无参数存储过程
    cursor.callproc('p2')  #等价于cursor.execute("call p2()")

    row_1 = cursor.fetchone()
    print row_1


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

b、调用有参存储过程


    #! /usr/bin/env python
    # -*- coding:utf-8 -*-
    # __author__ = "TKQ"

    import pymysql

    conn = pymysql.connect(host='127.0.0.1', port=3306, user='root', passwd='', db='tkq1')
    cursor = conn.cursor(cursor=pymysql.cursors.DictCursor)

    cursor.callproc('p1', args=(1, 22, 3, 4))
    #获取执行完存储的参数,参数@开头
    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()

三、关于pymysql防注入

1、字符串拼接查询,造成注入

正常查询语句:


    #! /usr/bin/env python
    # -*- coding:utf-8 -*-
    # __author__ = "TKQ"
    import pymysql

    conn = pymysql.connect(host='127.0.0.1', port=3306, user='root', passwd='', db='tkq1')
    cursor = conn.cursor()
    user="u1"
    passwd="u1pass"
    #正常构造语句的情况
    sql="select user,pass from tb7 where user='%s' and pass='%s'" % (user,passwd)
    #sql=select user,pass from tb7 where user='u1' and pass='u1pass'
    row_count=cursor.execute(sql) row_1 = cursor.fetchone()
    print row_count,row_1

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

构造注入语句:


    #! /usr/bin/env python
    # -*- coding:utf-8 -*-
    # __author__ = "TKQ"
    import pymysql

    conn = pymysql.connect(host='127.0.0.1', port=3306, user='root', passwd='', db='tkq1')
    cursor = conn.cursor()

    user="u1' or '1'-- "
    passwd="u1pass"
    sql="select user,pass from tb7 where user='%s' and pass='%s'" % (user,passwd)

    #拼接语句被构造成下面这样,永真条件,此时就注入成功了。因此要避免这种情况需使用pymysql提供的参数化查询。
    #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()

2、避免注入,使用pymysql提供的参数化语句

正常参数化查询


    #! /usr/bin/env python
    # -*- coding:utf-8 -*-
    # __author__ = "TKQ"

    import pymysql

    conn = pymysql.connect(host='127.0.0.1', port=3306, user='root', passwd='', db='tkq1')
    cursor = conn.cursor()
    user="u1"
    passwd="u1pass"
    #执行参数化查询
    row_count=cursor.execute("select user,pass from tb7 where user=%s and pass=%s",(user,passwd))
    row_1 = cursor.fetchone()
    print row_count,row_1

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

构造注入,参数化查询注入失败。


    #! /usr/bin/env python
    # -*- coding:utf-8 -*-
    # __author__ = "TKQ"
    import pymysql

    conn = pymysql.connect(host='127.0.0.1', port=3306, user='root', passwd='', db='tkq1')
    cursor = conn.cursor()

    user="u1' or '1'-- "
    passwd="u1pass"
    #执行参数化查询
    row_count=cursor.execute("select user,pass from tb7 where user=%s and pass=%s",(user,passwd))
    #内部执行参数化生成的SQL语句,对特殊字符进行了加\转义,避免注入语句生成。
    # sql=cursor.mogrify("select user,pass from tb7 where user=%s and pass=%s",(user,passwd))
    # print sql
    #select user,pass from tb7 where user='u1\' or \'1\'-- ' and pass='u1pass'被转义的语句。

    row_1 = cursor.fetchone()
    print row_count,row_1

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

结论:excute执行SQL语句的时候,必须使用参数化的方式,否则必然产生SQL注入漏洞。

3、使用存mysql储过程动态执行SQL防注入

使用MYSQL存储过程自动提供防注入,动态传入SQL到存储过程执行语句。


    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 tb2 where nid>? and nid<?';  传入的值为字符串,?为占位符
    --   用@p1,和@p2填充占位符
        EXECUTE myprod USING @nid1,@nid2;
      DEALLOCATE prepare myprod;

    END\\
    delimiter ;

    set @nid1=12;
    set @nid2=15;
    set @callsql = 'select * from tb7 where nid>? and nid<?';
    CALL proc_sql(@nid1,@nid2,@callsql)

pymsql中调用


    #! /usr/bin/env python
    # -*- coding:utf-8 -*-
    # __author__ = "TKQ"
    import pymysql

    conn = pymysql.connect(host='127.0.0.1', port=3306, user='root', passwd='', db='tkq1')
    cursor = conn.cursor()
    mysql="select * from tb7 where nid>? and nid<?"
    cursor.callproc('proc_sql', args=(11, 15, mysql))

    rows = cursor.fetchall()
    print rows #((12, 'u1', 'u1pass', 11111), (13, 'u2', 'u2pass', 22222), (14, 'u3', 'u3pass', 11113))
    conn.commit()
    cursor.close()
    conn.close()

四、使用with简化连接过程

每次都连接关闭很麻烦,使用上下文管理,简化连接过程


    #! /usr/bin/env python
    # -*- coding:utf-8 -*-
    # __author__ = "TKQ"

    import pymysql
    import contextlib
    #定义上下文管理器,连接后自动关闭连接
    @contextlib.contextmanager
    def mysql(host='127.0.0.1', port=3306, user='root', passwd='', db='tkq1',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()

    # 执行sql
    with mysql() as cursor:
      print(cursor)
      row_count = cursor.execute("select * from tb7")
      row_1 = cursor.fetchone()
      print row_count, row_1

总结

以上就是关于Python中pymysql模块的全部内容,希望对大家学习或使用python能有一定的帮助,如果有疑问大家可以留言交流。

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