Tkinter & mysql 的登录框练习

import tkinter as tk
from tkinter import messagebox
import pymysql

class SignIn(object):
    def __init__(self, root):
        self.root = root
        self.name = None
        self.password = None

    def the_Window(self, ):

        tk.Label(self.root, text=u"用户名(*):").grid(row=1, column=1, sticky='W')
        tk.Label(self.root, text=u"密码(*):").grid(row=2, column=1, sticky='W')
        self.name = tk.Entry(self.root)
        self.name.grid(row=1, column=2, sticky='W')
        self.password = tk.Entry(self.root, show="*")
        self.password.grid(row=2, column=2, sticky='W')
        tk.Button(self.root, text=u"登录", command=self.Login).grid(row=3, column=1, sticky='W')
        tk.Button(self.root, text=u"注册", command=self.Register).grid(row=3, column=2, sticky='W')
        tk.Label(self.root, text=u"(用户名只能出现字母，数字和下划线，不少于6位.)").grid(row=1, column=3, sticky='W')
        tk.Label(self.root, text=u"(密码只能出现字母，数字和下划线，不少于12位.)").grid(row=2, column=3, sticky='W')

    def Login(self):
        x = self.name.get()
        y = self.password.get()

        if len(x) == 0 or len(y) == 0:
            return
        conn = pymysql.Connect('localhost','root','','test',3306)

        sql_select = "select * from test_db"
        cur = conn.cursor()
        try:
            print(sql_select)
            cur.execute(sql_select)
            print(cur)

            rs = cur.fetchall()
            print(rs)

            for r in rs:
                if r[0] == x and r[1] == y:
                    messagebox.showinfo(title=u"登录成功", message=u"登录成功")
                    return
                elif r[0] == x and r[1] != y:
                    messagebox.showerror(title=u"错误信息", message=u"密码错误")
            messagebox.showerror(title=u"error", message=u"当前用户不存在")

        except Exception as e:
            print(e)

        finally:
            cur.close()
            conn.close()

    def Register(self):
        x = self.name.get()
        y = self.password.get()
        if len(x) == 0 or len(y) == 0:
            return
        self.name.delete(0)
        self.password.delete(0)
        # print x, y
        conn = pymysql.Connect('localhost','root','','test',3306)
        sql_select = "select username from test_db"
        sql_insert = 'insert test_db(username,password) values("%s", "%s")' % (x, y)
        cur = conn.cursor()
        try:
            cur.execute(sql_select)
            rs = cur.fetchall()
            flag = 0
            for r in rs:
                if r[0] == x:
                    flag = 1
                    messagebox.showinfo(title=u"用户名错误", message=u"当前用户名存在，请修改")
                    break
            if flag == 0:
                cur.execute(sql_insert)
                print(u"插入成功")

            conn.commit()

        except Exception as e:
            conn.rollback()
            print(e)
        finally:
            cur.close()
            conn.close()

if __name__ == "__main__":
    root = tk.Tk()
    sign = SignIn(root)
    sign.the_Window()

    root.mainloop()