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  • pymysql模块

    1.pymysql 模块

      1,安装:pip install pymysql

          pip -V 查看当前pip的版本

          pip list 查看当前python解释器环境中安装的第三方包和版本

      2.使用:

        

    import pymysql
    connect = connect.pymysql(
        host='localhost',
        port=3306,
        user='limi',
        password='123',
        database='db2',
        charset='utf8'
    )
    

    2 获取光标:

      cursor = conn.cursor()

    3.执行sql语句:

      ret = sursor.exxecute(sql)

    4.关闭:

      关闭光标

        cursor.close()

      关闭连接:

        conn.close()

    5.sql注入:

      1.什么是SQL语句注入

        用户输入的内容有恶意的sql语句,后端拿到用户输入的内容不做检测直接做字符串拼接,得到一个

        和预期不一致的SQL语句

      2.怎么解决sql注入

                  对用户输入的内容进行检测

        pymysql内置了这种检测,我们只需要让pymysql帮我们拼接sql语句即可.

    6.pymysql的使用

      登录校验

        

    import pymysql
    conn = pymysql.connect(
        host='localhost',
        port=3306,
        user='limi',
        password='123',
        database='db2',
        charset='utf8'
    )
    cursor = conn.cursor()
    sql = "select * from userinfo where  name = %s and password = %s;"
    ret = cursor.execute(sql,['liming','123'])
    cursor.close()
    conn.close()
    if ret:
        print('登录成功')
    else:
        print('登录失败')
    

      增

    import pymysql
    conn = pymysql.connect(
        host='localhost',
        port=3306,
        user='limi',
        password='123',
        database='db2',
        charset='utf8'
    )
    cursor = conn.cursor()
    sql = "insert into userinfo (name,password) values (%s,%s);"
    ret = cursor.execute(sql,['litianyi','123'])
    #  conn.rollback()  # 回滚
    conn.commit()  # 提交
    cursor.close()
    conn.close()
    

      删

    import pymysql
    conn = pymysql.connect(
        host='localhost',
        port=3306,
        user='limi',
        password='123',
        database='db2',
        charset='utf8'
    )
    cursor = conn.cursor()
    sql = "delete from userinfo where name = %s;"
    ret = cursor.execute(sql,['litian'])
    conn.commit()
    conn.close()
    cursor.close()
    

      改

    import pymysql
    conn = pymysql.connect(
        host='localhost',
        port=3306,
        user='limi',
        password='123',
        database='db2',
        charset='utf8'
    )
    cursor = conn.cursor()
    sql = "update userinfo set password = %s where name = %s;"
    ret = cursor.execute(sql,['123456','litianyi'])
    conn.commit()
    conn.close()
    cursor.close()
    

      查

    import pymysql
    conn = pymysql.connect(
        host='localhost',
        port=3306,
        user='limi',
        password='123',
        database='db2',
        charset='utf8'
    )
    cursor = conn.cursor()  # 默认以元祖返回
    sql = "select * from userinfo;"
    cursor.execute(sql)
    ret = cursor.fetchall()  # 获取所有查询回来的值
    print(ret)
    conn.close()
    cursor.close()
    

      

    import pymysql
    conn = pymysql.connect(
        host='localhost',
        port=3306,
        user='limi',
        password='123',
        database='db2',
        charset='utf8'
    )
    cursor = conn.cursor(cursor=pymysql.cursors.DictCursor)  # 以字典形式返回
    sql = "select * from userinfo;"
    cursor.execute(sql)
    ret = cursor.fetchone()
    print(ret)
    ret = cursor.fetchmany(2)  # 两个放回值
    print(ret)
    conn.close()
    cursor.close()
    

      

    cursor.scroll(0,mode='absolute') 绝对位置,你让光标移动到哪里

    cursor.scroll(-1,mode='relative') 相对位置,基于光标当前位置移动

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  • 原文地址:https://www.cnblogs.com/lijinming110/p/9757000.html
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