deletecode File for Delete Data in PHP

 <?php

include("mysqli_conn.php");

if (isset($_POST["deletedata"])) {

    $id = $_POST["delete_id"];

    $sql = "DELETE FROM student WHERE id=$id";

    if ($conn->query($sql) == TRUE) {

        echo "<script>alert('Data Deleted');</script>";

        header("Location:index.php");

    } else {

        echo "<script>alert('Data Not Deleted');</script>";

    }

}