Question

我正在尝试使用Python与MySQL数据库建立连接在RaspberryPi上。我是面向对象python的新手。我在这段代码中将值作为输入并尝试将其插入数据库中。应有对某些问题，插入查询没有被执行和 Exception部分正在执行。请帮我识别我的错误。

import tkinter as tk
import MySQLdb   

class ImgComp(tk.Tk):

    def __init__(self, *args, **kwargs):
        tk.Tk.__init__(self, *args, **kwargs)        
        container = tk.Frame(self,width=320, height=209)        
        container.pack(side="top")
        container.grid_rowconfigure(0, weight=1)
        container.grid_columnconfigure(0, weight=1)
        container.grid_propagate(False)

        try:
            self.db = MySQLdb.connect("localhost","root","root","sample")
            self.c= self.db.cursor()                
        except:
            print ("I can't connect to MySql")
        self.frames = {}
        for F in (InputPage):            
            frame = F(container, self)                
            self.frames[F] = frame            
            frame.grid(row=0, column=0, sticky="nsew")
        self.show_frame(InputPage)   

    def show_frame(self, cont):
        frame = self.frames[cont]                    
        if ((cont == PageOne) | (cont == InputPage) | (cont == OutputPage)):            
            self['menu'] = frame.menubar                
        else: 
            self['menu'] = ''            
        frame.tkraise()

    def input_submit(self, input_value):            

        in_val = float(input_value)
        self.sql = "INSERT INTO input_delay_master (input_delay) VALUES (%s)"                
        try:                   
            c.execute(self.sql,(in_val))                    
            self.db.commit()
        except:                    
            print("Except")
            self.db.rollback()         

class InputPage(tk.Frame):

    def __init__(self, parent, controller):
        tk.Frame.__init__(self, parent)
        self.menubar = tk.Menu()
        filemenu = tk.Menu(self.menubar, tearoff=0)            
        filemenu.add_command(label="Output Reset Delay", command=lambda: controller.show_frame(OutputPage))                        
        self.menubar.add_cascade(label="Settings", menu=filemenu)        
        label = tk.Label(self, text="Input Image Delay")
        label.pack(pady=10,padx=10)                       
        input_delay = tk.Entry(self)
        input_delay.pack(pady=10)
        submit1 = tk.Button(self, text = "Submit", command=lambda: controller.input_submit(input_delay.get()))
        submit1.pack()

我得到以下输出

34.56 # This is the the value I entered in Entry field    

Except

问题是，input_submit按钮中存在的插入查询未执行，而是执行了Expection部分。请帮助我找到成功执行插入查询的方法。

Answer 1

except期望tuple带参数 - 即使你只有一个参数 - 但(in_val)不是元组，它是单个元素。要创建tuple，您需要在(in_val, )

中添加逗号

Python MySQLdb面向对象

1 个答案: