React prevent Duplicate record input? - mysql

Question

How i can prevent duplicate record input especially email and student number And show the message if the registration is accepted or it has duplicate record?
It accept data and when a set the email and the student number unique in the MySQL db it will not accept data but their is no message. It only show message in the terminal of visual studio that the email and student number is unique
Front end
import React from 'react'
import { useState } from 'react';
import Axios from 'axios';
import { useNavigate} from 'react-router-dom'
function Register() {
let navigate= useNavigate();
const [email, setEmail] = useState("");
const [password, setPassword] = useState("");
const [student_num , setStudnum] = useState(0);
const [RegisterStatus, setRegisterStatus] = useState("");
const [studentList, setStudentList] = useState([])
const addStudent = ( ) =>{
Axios.post("http://localhost:3001/create", {
email: email,
password: password,
student_num : student_num ,
}).then(()=>{
console.log("sucess")
});
};
return (
<form>
<div className="information">
<div className="App">
<label>Email:</label>
<input type="text" onChange={(event) => {
setEmail(event.target.value);
}} required />
<label>Password:</label>
<input type="password" onChange={(event) => {
setPassword(event.target.value);
}} required/>
<label>Student Number:</label>
<input type="number" onChange={(event) => {
setStudnum(event.target.value);
}}required/>
This is the MySQL connection / backend
app.post("/create", (req, res) => {
const email = req.body.email;
const password = req.body.password;
const student_num = req.body.student_num;
db.query(
"INSERT INTO student (email,passwordstudent_num) VALUES (?,?,?)",
[
email,
password,
student_num,
],
(err, result) => {
if (err) {
console.log(err);
} else {
res.send("Values Inserted");
}
}
);
});