我用python连接数据库，当数据库的服务关闭的时候，程序会卡死。怎么提前判定数据是否开启？如果没有开启就返回值。

试过用try except,但是好像没有用,login_timeout也用了感觉也不对。照样卡死

相关代码

import winsound
import xlwt
import pymssql
import tkinter as tk
window = tk.Tk()
window.title('my window')
window.geometry('300x300')
e = tk.Entry(window, show=None)
e.pack()
def set_style(name, height, bold=False):

style = xlwt.XFStyle()
font = xlwt.Font()
font.name = name
font.bold = bold
font.color_index = 4
font.height = height
style.font = font
return style

def write_excel(d):

f = xlwt.Workbook()
sheet1 = f.add_sheet('学生',cell_overwrite_ok=True)
row0 = ["id","username","age"]
#写第一行
for i in range(0,len(row0)):
    sheet1.write(0,i,row0[i],set_style('Times New Roman',220,True))
#从第二行开始写从数据库里面捞出来的数据
for i in range(0,len(d)):
    for m in range(0, len(d[i])):
        sheet1.write(i + 1, m, d[i][m], set_style('Times New Roman', 220, True))
f.save('F:/'+tt+'.xls',)

global Mes1
Mes1 = None
def insert_point():

conn = pymssql.connect(host="ddd", user='sa', password='ddd', database='master',login_timeout=10)
try:
    cur = conn.cursor()
    global tt
    tt=e.get()
    if e.get()=='':
        show_eff(False)
    else:
        cur.execute('select * from temp_ross where id=%s', (e.get()))
        data = cur.fetchall()
        if len(data) !=0:
            t = []
            d = []
            for i in range(len(data)):
                t.append(data[i][0])
                t.append(data[i][1].rstrip())
                t.append(data[i][2])
                d.append(t)
                t = []
            write_excel(d)
            cur.close()
            show_eff(True)
        else:
            show_eff(False)
except pymssql.OperationalError:
    show_eff(False)

def show_eff(e):

global Mes1
if Mes1 is None:
    Mes1 = tk.Message(text = 'OK' if e else 'Fail', width = 60)
    Mes1.pack()
else:
    Mes1.pack_forget()
    Mes1 = tk.Message(text = 'OK' if e else 'Fail', width = 60)
    Mes1.pack()
if e==False:
    winsound.Beep(900, 1000)

def windowset():

b1 = tk.Button(window, text='insert point', width=15,
               height=2, command=insert_point)
b1.pack()
window.mainloop()

windowset()

能否有方法判断出数据库是否开启