update.php

<?php
include('ai.php');

if (isset($_POST['updateemployee'])) {
    $id = $_POST['update_id'];
    $name = $_POST['update_name'];
    $department = $_POST['update_dept'];
    $salary = $_POST['update_sal'];

    $check_query = "SELECT * FROM `employee` WHERE `Id` = '$id'";
    $check_result = mysqli_query($connection, $check_query);

    if (mysqli_num_rows($check_result) == 0) {
        header('Location: name.php?message=ID does not exist');
        exit();
    } else {
        $query = "UPDATE `employee` 
                  SET `Name` = '$name', `Department` = '$department', `Salary` = '$salary' 
                  WHERE `Id` = '$id'";

        $result = mysqli_query($connection, $query);

        if ($result) {
            header('Location: name.php?insert_msg=Data Is Updated Successfully!');
            exit();
        } else {
            die("Query Failed: " . mysqli_error($connection));
        }
    }
}
?>