当我按下按钮时，只有最后按下的按钮将我保存在csv文件中。如何在csv中保存所有数据？

Question

我想通过一些按钮创建一个数据库

def functie(Tip_suprafata, Prelucrare):
    
    with open('employee_file2.csv', mode='w') as csv_file:
            fieldnames = ['Tip_suprafata', 'Prelucrare']
            reader = csv.reader(csv_file, delimiter=' ', quotechar='|')
            writer = csv.DictWriter(csv_file, fieldnames=fieldnames)

class Pag1(tk.Frame):

    def __init__(self, parent, controller):
        tk.Frame.__init__(self, parent)
        label = tk.Label(self, text="Alege prelucrarea")
        label.pack(pady=20,padx=20)
        self.controller = controller
        label = tk.Label(self, text="This is page 1")
        button = tk.Button(self, text="Găurire", command=lambda: functie('conica2', 'gaurire'))
        button1 = tk.Button(self, text="Frezare",
                           command=lambda: functie('conica3', 'gaurire2'))
        button2 = tk.Button(self, text="Rectificare",
                           command=lambda: functie('conica4', 'gaurire6'))
        button.pack()
        button1.pack()
        button2.pack()


class Pag2(tk.Frame):

    def __init__(self, parent, controller):
            tk.Frame.__init__(self, parent)
            label = tk.Label(self, text="Alege prelucrarea")
            label.pack(pady=20,padx=20)
            self.controller = controller
            label = tk.Label(self, text="This is page 2")
            button = tk.Button(self, text="Găurire", command=lambda: functie('bulangerie', 'gaurire'))
            button.pack()


            row_count = sum(1 for row in open('employee_file2.csv'))
               
            writer.writeheader()
            writer.writerow({'Tip_suprafata': Tip_suprafata, 'Prelucrare': Prelucrare})