Tkinter中SQLite3数据无法在Treeview表格显示问题求助

程序可正常将数据插入Employees.db数据库（已手动打开数据库确认数据写入正确），但Tkinter的Treeview表格无法显示数据库中的数据。

相关代码 #

lab.py #

def add_to_treeview():
    employees = database.fetch_employees()
    tree.delete(*tree.get_children())
    for employee in employees:
        tree.insert('', END, values=employee)

def insert():
    id = id_entry.get()
    name = name_entry.get()
    role = role_entry.get()
    gender = variable1.get()
    status = status_entry.get()
    if not (id and name and role and gender and status):
        messagebox.showerror('Error', 'Enter all fields.')
    elif database.id_exists(id):
        messagebox.showerror('Error', 'ID already exists.')
    else:
        database.insert_employee(id,name,role,gender,status)
        add_to_treeview()
        messagebox.showinfo('Success', 'Data has been inserted.')

style = ttk.Style(app)

style.theme_use('clam')
style.configure('Treeview', font=font2,foreground='#aaa',background='#000',fieldbackground='#313837')
style.map('Treeview',background=[('selected', '#1A8F2D')])

tree = ttk.Treeview(app,height=15)#9)

tree['columns'] = ('ID', 'Name', 'Role', 'Gender', 'Status')

tree.column('#0', width=0, stretch=tk.NO)
tree.column('ID', anchor=tk.CENTER, width=120)
tree.column('Name', anchor=tk.CENTER, width=120)
tree.column('Role', anchor=tk.CENTER, width=120)
tree.column('Gender', anchor=tk.CENTER, width=100)
tree.column('Status', anchor=tk.CENTER, width=120)

tree.heading('ID', text='ID')
tree.heading('Name', text='Name')
tree.heading('Role', text='Role')
tree.heading('Gender', text='Gender')
tree.heading('Status', text='Status')

tree.place(x=300,y=20)#60,y=20)

add_to_treeview()

app.mainloop()

database.py #

import sqlite3

def create_table():
    conn = sqlite3.connect('Employees.db')
    cursor = conn.cursor()

    cursor.execute('''
        CREATE TABLE IF NOT EXISTS Employees (
            id TEXT PRIMARY KEY,
            name TEXT,
            role TEXT,
            gender TEXT,
            status TEXT)''')
    conn.commit()
    conn.close()

def fetch_employees():
    conn = sqlite3.connect('Employees.db')
    cursor = conn.cursor()
    cursor.execute('SELECT * FROM Employees')
    employees = cursor.fetchall()
    conn.close()
    return employees

def insert_employee(id, name, role, gender, status):
    conn = sqlite3.connect('Employees.db')
    cursor = conn.cursor()
    cursor.execute('INSERT INTO Employees (id, name, role, gender, status) VALUES (?,?,?,?,?)',
                   (id, name, role, gender, status))
    conn.commit()
    conn.close()

截图说明 #

• 程序预期效果：Treeview表格中显示完整的员工数据列表
• 程序当前状态：Treeview表格为空，无任何数据内容显示

内容的提问来源于stack exchange，提问作者Канат Муратов