Getting Data Mismatch error in sqlite and tkinter

I am making a simple contact book with tkinter and sqlite3. It has not been completed yet. I am getting an error which I did not get on my previous project. Here is my code below:

Backend:

import sqlite3

def connect():
    conn=sqlite3.connect("book.db")
    cur=conn.cursor()
    cur.execute("CREATE TABLE IF NOT EXISTS contact (name text, number integer, id integer,email text)")
    conn.commit()

def view():
    conn=sqlite3.connect("book.db")
    cur=conn.cursor()
    cur.execute("SELECT * FROM contact")
    rows=cur.fetchall()
    conn.close()
    return rows

def search(name="", number="", email="", id=""):
    conn=sqlite3.connect("book.db")
    cur=conn.cursor()
    cur.execute("SELECT * FROM contact WHERE name=? OR number=? or email=? OR id=?",(name,number,email,id))
    rows=cur.fetchall()
    conn.close()
    return rows

def insert(name="", number="", email="", id=""):
    conn=sqlite3.connect("book.db")
    cur=conn.cursor()
    cur.execute("INSERT INTO contact VALUES(?,?,?,?)", (name,number,email,id))
    conn.commit()
    conn.close()

def update(name="", number="", email="", id=""):
    conn=sqlite3.connect("book.db")
    cur=conn.cursor()
    cur.execute("UPDATE contact SET name=?, number=?, email=? WHERE id=?",(name,number,email,id))
    conn.commit()
    conn.close()
def delete(id):
    conn=sqlite3.connect("book.db")
    cur=conn.cursor()
    cur.execute("DELETE FROM contact WHERE id=?",(id,))
    conn.commit()
    conn.close()


connect()

And my frontend:

from tkinter import *
import webbrowser
import backend

def view_command():
    list1.delete(0,END)
    for row in backend.view():
        list1.insert(END,row)

def add_command():
    backend.insert(name_text.get(), contact_text.get(), email_text.get(),ID_text.get())
    list1.delete(0,END)
    for rows in backend.search(name_text.get(), contact_text.get(), email_text.get(),ID_text.get()):
        list1.insert(rows, END)
    e1.delete(0,END)
    e2.delete(0,END)
    e3.delete(0,END)
    e4.delete(0,END)




window=Tk()

window.wm_title("Contact book")

window.iconbitmap(r'C:\Anirudh\Python\School\project\icon.ico')


l1=Label(window,text="Name")
l1.grid(row=0,column=0)

l2=Label(window,text="Contact")
l2.grid(row=0,column=2)

l3=Label(window,text="Email")
l3.grid(row=1,column=0)

l4=Label(window,text="ID")
l4.grid(row=1,column=2)

name_text=StringVar()
e1=Entry(window,textvariable=name_text)
e1.grid(row=0,column=1)

contact_text=StringVar()
e2=Entry(window,textvariable=contact_text)
e2.grid(row=0,column=3)

email_text=StringVar()
e3=Entry(window,textvariable=email_text)
e3.grid(row=1,column=1)

ID_text=StringVar()
e4=Entry(window,textvariable=ID_text)
e4.grid(row=1,column=3)

list1=Listbox(window, height=10,width=35)
list1.grid(row=2,column=0,rowspan=6,columnspan=2)

sb1=Scrollbar(window)
sb1.grid(row=2,column=2,rowspan=6)

list1.configure(yscrollcommand=sb1.set)
sb1.configure(command=list1.yview)

sb2=Scrollbar(window, orient='horizontal', bg="red")
sb2.grid(row=8,column=1, rowspan=6)

list1.configure(xscrollcommand=sb2.set)
sb2.configure(command=list1.xview)


b1=Button(window,text="View all", width=12,command=view_command)
b1.grid(row=2,column=3)

b2=Button(window,text="Search entry", width=12)
b2.grid(row=3,column=3)

b3=Button(window,text="Add entry", width=12, command=add_command)
b3.grid(row=4,column=3)

b4=Button(window,text="Update selected", width=12)
b4.grid(row=5,column=3)

b5=Button(window,text="Delete selected", width=12)
b5.grid(row=6,column=3)

b6=Button(window,text="Whatsapp", width=12, bg="green")
b6.grid(row=7,column=3)

b7=Button(window,text="Close", width=12,command=window.destroy)
b7.grid(row=8,column=3)


window.mainloop()

I have not yet completed it... When I try to add some contact to the database I get the following error.

PS C:\Anirudh\Python\School\project> python frontend.py
Exception in Tkinter callback
Traceback (most recent call last):
  File "C:\Users\aayan\AppData\Local\Programs\Python\Python38-32\lib\tkinter\__init__.py", line 1883, in __call__
    return self.func(*args)
  File "frontend.py", line 11, in add_command
    backend.insert(name_text.get(), contact_text.get(), email_text.get(),ID_text.get())
  File "C:\Anirudh\Python\School\project\backend.py", line 28, in insert
    cur.execute("INSERT INTO contact VALUES(?,?,?,?)", (name,number,email,id))
sqlite3.IntegrityError: datatype mismatch

Thanks.