python-mysql数据库登录与注册练习

import hashlib,pymysql,datetime
def my_db(sql):
    import pymysql
    coon = pymysql.connect(
        host = '118.24.3.40',user = 'jxz',passwd = '123456',
        port = 3306,db = 'jxz',charset = 'utf8'
    )
    cur = coon.cursor()#建立游标
    cur.execute(sql)#执行sql
    if sql.strip()[:6].upper() == 'SELECT':
        res = cur.fetchall()
    else:
        coon.commit()
        res = 'ok'
    cur.close()
    coon.close()
    return res

def my_md5(str):
    import hashlib
    new_str = str.encode()#吧字符串转成bytes类型
    m = hashlib.md5()#实例化md5对象
    m.update(new_str)#加密
    return m.hexdigest()#获取返回结果

def reg():
    username = input("username:").strip()
    pwd = input("pwd:").strip()
    cpwd = input('cpwd:').strip()
    if username and pwd and cpwd:
        sql = 'select * from nhy where name = "%s";'%username
        res = my_db(sql)
        if res:
            print("该用户已经存在！")
        else:
            if pwd == cpwd:
                md5_pwd = my_md5(pwd)
                insert_sql = 'insert into nhy (name,pwd) values ("%s","%s");'%(username,md5_pwd)
                my_db(insert_sql)
                print("注册成功！")
            else:
                print('两次输入的密码不一致！')
    else:
        print('必填项不能为空！')

def login():
    username = input('username:').strip()
    pwd = input('pwd:').strip()
    if username and pwd:
        md5_pwd = my_md5(pwd)
        sql = 'select * from nhy where name = "%s" and pwd = "%s";'%(username,md5_pwd)
        res = my_db(sql)
        if res:
            print("欢迎，登陆成功！今天是%s"%datetime.date.today())
        else:
            print('账号或密码错误')
    else:
        print("必填项不能为空！")
#login()
reg()