我是 Tkinter 的新手，并試圖創建一個函數，該函數將連接到我的 GUI 中的“提交”按鈕，以便它將數據輸入到我的 MySQL 數據庫中。反饋告訴我，'itemCode_entry' is not defined在def inv_submit():函數中。我試圖itemCode_entry從def inv_menu():函數中獲取輸入并將其輸入到def inv_submit():MySQL 語句中。這是我得到的反饋。Exception in Tkinter callbackTraceback (most recent call last):  File "C:\Users\darre\AppData\Local\Programs\Python\Python37\lib\tkinter\__init__.py", line 1702, in __call__    return self.func(*args)  File "Import_Test_Code2.py", line 103, in <lambda>    submit_btn = Button(btm_frame, text='Submit', bg=color1, command= lambda : inv_submit())  File "Import_Test_Code2.py", line 207, in inv_submit    item = itemCode_entry.get()NameError: name 'itemCode_entry' is not definedfrom tkinter import *import mysql.connector#  ======================MySQL Connection================================================================mydb = mysql.connector.connect(    host = "localhost",    user = "root",    passwd = "....",    database = "testdb",    )# Create Cursor Instancemy_cursor = mydb.cursor()# Create Database#my_cursor.execute("CREATE DATABASE trialProjectdb")root = Tk()root.geometry('500x500')root.title('Database Control')color1 = 'grey77'color2 = 'grey88'item = int()brandName = StringVar()#unitsPer = int()units = int()cost = float()#  ======================Frames================================================================top_frame = Frame(root, width=500, height=80, bg=color1)top_frame.pack(side=TOP)btm_frame = Frame(root, width=500, height=500, bg=color2)btm_frame.pack(side=TOP)#  ======================Inventory=============================================================inv_btn = Button(top_frame, text='Inventory', width=20,             command= lambda : inv_menu())inv_btn.place(x=0, y=0)submit_btn一旦我在“庫存”表單中填寫了信息，我希望“提交”按鈕將數據提交給 MySQL 以更新數據庫inv_menu()。