Deleting record from MySQL table using Treeview Selection

• Delete Selected row from Treeview & from MySQL database

selected_item = trv.selection()[0]

query="DELETE FROM  student WHERE id=%s"
rs=my_conn.execute(query,selected_item)

if(rs.rowcount==1):
            trv.delete(selected_item)

from tkinter import ttk
import tkinter as tk
from sqlalchemy import create_engine
from sqlalchemy.exc import SQLAlchemyError
my_conn = create_engine("mysql+mysqldb://userid:pw@localhost/my_db")
r_set=my_conn.execute('SELECT * FROM student LIMIT 0,10')
my_w=tk.Tk()
my_w.geometry('400x350')
my_w.title("www.plus2net.com")
trv=ttk.Treeview(my_w,selectmode='browse')
trv.grid(row=1,column=1,padx=20,pady=20)
trv["columns"]=("1","2","3","4","5")
trv['show']='headings'
#trv['show']='tree'
trv.column("1",width=30,anchor='c')
trv.column("2",width=80,anchor='c')
trv.column("3",width=80,anchor='c')
trv.column("4",width=80,anchor='c')
trv.column("5",width=80,anchor='c')
trv.heading("1",text="id")
trv.heading("2",text="Name")
trv.heading("3",text="Class")
trv.heading("4",text="Mark")
trv.heading("5",text="Gender")

for dt in r_set:
    #print(dt)
    trv.insert("",'end',iid=dt[0],
		values=(dt[0],dt[1],dt[2],dt[3],dt[4]))

b1 = tk.Button(my_w, text='delete row', width=20,bg='yellow',
    command=lambda: delete())
b1.grid(row=2,column=1)
my_font=('times', 10, '')
my_str = tk.StringVar()
l1 = tk.Label(my_w,  textvariable=my_str, font=my_font)
l1.config(fg='blue')
l1.grid(row=3,column=1)
my_str.set("Message here")#print(my_error)
def delete():
    selected_item = trv.selection()[0] ## get selected item
    try:
        query="DELETE FROM  student WHERE id=%s"
        rs=my_conn.execute(query,selected_item)
        if(rs.rowcount==1):
            trv.delete(selected_item) #delete from Treeview
            l1.config(fg='green') # message font colour
            my_str.set("Record deleted")#Message 
    except SQLAlchemyError as e:
        error=str(e.__dict__['orig'])
        l1.config(fg='red')
        my_str.set(error)        
    l1.after(3000, lambda: my_str.set('') ) # remove the message
l1.after(3000, lambda: my_str.set('') )
my_w.mainloop()