pymsql模块详解

pymysql是python提供的一个mysql客户端模块,用于与mysql服务器建立连接,发送查询,并获取结果等;

基本使用:

import pymysql
# 1.建立连接
try:
    conn = pymysql.connect(host="127.0.0.1",port=3306,user="root",password="",db="day46",)
    print("连接服务器成功!")
    #2.获取游标对象
    cursor = conn.cursor()
    #3.执行sql语句
    count = cursor.execute("select *from user")
    print("结果数量: %s" % count)

    # 提取结果
    # print(cursor.fetchall())
    # print(cursor.fetchone())
    # print(cursor.fetchmany(1))

    # 移动游标位置  相对当前位置
    cursor.scroll(1,"relative")
    cursor.scroll(-1, "relative")
    print(cursor.fetchone())

    # 移动游标位置  使用绝对位置
    cursor.scroll(0, "absolute")
    print(cursor.fetchone())

    print(cursor.fetchall())
    # 注意 游标移动到末尾后无法在读取到数据 若需重复读取数据,需要使用scroll来移动游标

except Exception as e:
    print("连接服务器失败.....")
    print(type(e),e)
finally:
    if cursor:
        cursor.close()
        print("关闭游标")
    if conn:
        conn.close()
        print("关闭链接")

为了防止SQL注入攻击，我们使用pymsql封装好的功能，下面是改良版

try:
    conn = pymysql.connect(host="127.0.0.1",port=3306,user="root",password="",db="day46",)
    print("连接服务器成功!")
    cursor = conn.cursor(pymysql.cursors.DictCursor)
    
    user = input("username:")
    password = input("password:")

    sql = "select *from user where name = %s and password = %s"
    print(sql)
    count = cursor.execute(sql,(user,password)) # 参数交给模块
    if count:
        print("登录成功!")
    else:
        print("登录失败!")
except Exception as e:
    print(type(e),e)
finally:
    if cursor:cursor.close()
    if conn: conn.close()