basic crud php

<?php

$mysqli = new mysqli('localhost', 'root', '', 'crud_test') or die(mysqli_error($mysqli));
session_start();

$update = false;
$id = 0;
$location = '';
$name = '';

if(isset($_POST['save']))
{
    $name = $_POST['name'];
    $location = $_POST['location'];
    $mysqli->query("INSERT INTO data(name, location) VALUES('$name', '$location' )") or die($mysqli->error);

    $_SESSION['message'] = "Data succesfully inserted.";
    $_SESSION['msg_type'] = "Success:";

    header("location: index.php");
}

if(isset($_POST['update']))
{
    $id = $_POST['id'];
    $name = $_POST['name'];
    $location = $_POST['location'];

    $mysqli->query("UPDATE data SET name='$name', location='$location' WHERE id = $id") or die($mysqli->error);

    $_SESSION['message'] = "Data succesfully Updated.";
    $_SESSION['msg_type'] = "Success:";

    header("location: index.php");
}

if(isset($_GET['edit']))
{
    $id = $_GET['edit'];
    $result = $mysqli->query("SELECT * FROM data WHERE id=$id") or die($mysqli->error);
    $row = $result->fetch_array();
    $name = $row['name'];
    $location = $row['location'];
    $update = true;
}

if(isset($_GET['delete']))
{
    $id = $_GET['delete'];
    $mysqli->query("DELETE FROM data WHERE id=$id") or die($mysqli->error);

    $_SESSION['message'] = "Data succesfully Deleted.";
    $_SESSION['msg_type'] = "Information:";

    header("location: index.php");
}

?>

<!DOCTYPE html>
<html>
    <head>
        <title>Crud test</title>
    </head>
    <body>
    <?php
        require_once "process.php";
        $mysqli = new mysqli('localhost', 'root', '', 'crud_test') or die(mysqli_error($mysqli));
        $result = $mysqli->query("SELECT * FROM data") or die($mysqli->error);

        if(isset($_SESSION['message']))
        {
            echo $_SESSION['msg_type'] . " " . $_SESSION['message'];
            unset($_SESSION['message']);
        }
    ?>
        <form action="process.php" method="POST">
            <input type="hidden" name="id" value="<?php echo $id; ?>">
            <input type="text" placeholder="name" value="<?php echo $name; ?>"  name="name">
            <input type="text" placeholder="location" value="<?php echo $location; ?>" name="location">
            <?php
                if($update == true)
                {
                    echo "<button type='submit' name='update'>Update</button>";
                }
                else
                {
                    echo "<button type='submit' name='save'>Save</button>";
                }
            ?>
        </form>

        <table>
            <thead>
                <tr>
                    <td>Name</td>
                    <td>Location</td>
                    <td>Action</td>
                </tr>
            </thead>
            <tbody>
                <?php
                    while($row = $result->fetch_assoc())
                    {
                        echo "<tr>";
                        echo "<td>{$row['name']}</td>";
                        echo "<td>{$row['location']}</td>";
                        echo "<td><a href='index.php?edit={$row['id']}'>Edit</a>
                                  <a href='process.php?delete={$row['id']}'>Delete</a></td>";
                        echo "</tr>";
                    }
                ?>
            </tbody>
        </table>
    </body>

</html>