Interfacing SQL with Python : Update Record

import mysql.connector as cn

con=cn.connect(host='localhost',user='root',password='root',database='stud_db')

if con.is_connected():

    print("connected to the database....")

cr=con.cursor()

print("==============Program to Update record==============")

rn=int(input("Enter roll no. to update:"))

marks=int(input("Enter New Marks:"))

cr.execute("update student set marks=%s where rollno=%s"%(marks,rn))

con.commit()

cr.execute("select * from student")

data=cr.fetchall()

for rec in data:

   print(rec)