Error :unable to detect undefined names created in spyder ide error at line 2

[milind_eac]

import pymysql
from tkinter import *
from tkinter import messagebox
def search():
    try:
        con=pymysql.connect(user='root',password='Sanjay1*',host='localhost',database='mydatabase')
        cur=con.cursor()
        sql="select * from student where rollnoo='%s'"%rollno.get()
        cur.execute(sql)
        result=cur.fetchone()
        name.set(result[1])
        age.set(result[2])
        e1.configure(state='disabled')
        con.close()
    except:
        messagebox.showinfo('No data avl')
        clear()
def clear():
    rollno.set('')
    name.set('')
    age.set('')
    e1.configure(state='normal')
def add():
    try:
        con=pymysql.connect(user='root',password='Sanjay1*',host='localhost',database='mydatabase')
        cur=con.cursor()
        sql="insert into student values('%s','%s','%s')"%(rollno.get(),name.get(),age.get())
        cur.execute(sql)
        con.commit()
        con.close()
        messagebox.showinfo('success','Record save...')
    except:
        messagebox.showinfo('Error', 'Error in dataentry')
    finally:
        clear()
def update():
    try:
        con=pymysql.connect(user='root',password='Sanjay1*',host='localhost',database='mydatabase')
        cur=con.cursor()
        sql="update student set name = '%s',age='%s' where rollno='%s'" %(name.get(),age.get(),rollno.get())
        cur.execute(sql)
        con.commit()
        con.close()
        messagebox.showinfo('success','Record updated...')
    except:
        messagebox.showinfo('Error', 'Error in dataentry')
    finally:
        clear()
def delete():
    try:
        con=pymysql.connect(user='root',password='Sanjay1*',host='localhost',database='mydatabase')
        cur=con.cursor()
        sql="delete from student where rollno='%s'" %(rollno.get())
        cur.execute(sql)
        con.commit()
        con.close()
        messagebox.showinfo('success','Record deleted...')
    except:
        messagebox.showinfo('Error', 'Error in dataentry')
    finally:
        clear()
w1=Tk()
w1.title('My App')
w1.geometry('500x200')

ptitle=Label(w1,text='''Program to add, modify, delete the records from student table''')

ptitle.grid(row=0,column=0,columnspan=2)

rollno=StringVar()
name=StringVar()
age=StringVar()

l1=Label(w1,text=' RollNo ')
e1=Entry(w1, textvariable=rollno)
l2=Label(w1,text=' Name ')
e2=Entry(w1, textvariable=name)
l3=Label(w1,text=' Age ')
e3=Entry(w1, textvariable=age)

b1=Button(w1,text=' search ', command=search)
b2=Button(w1,text=' Add    ', command=add)
b3=Button(w1,text=' Update ', command=update)
b4=Button(w1,text=' Delete ', command=delete)
b5=Button(w1,text=' clear  ', command=clear)

l1.grid(row=1,column=0)
e1.grid(row=1,column=1)
b1.grid(row=1,column=2)

l2.grid(row=2,column=0)
e2.grid(row=2,column=1)

l3.grid(row=3,column=0)
e3.grid(row=3,column=1)

b2.grid(row=4,column=0)
b3.grid(row=4,column=1)
b4.grid(row=5,column=0)
b5.grid(row=5,column=1)
w1.mainloop()

Error:
Error :unable to detect undefined names created in spyder ide
error at line 2
Error : Tk may be undefined or defined from star imports : tkinter