<?php 
require_once './db.php'; 
 
/** Usually you do this */ 
// $userId = filter_input(INPUT_GET, 'user_id', FILTER_VALIDATE_INT); 
/** For the sake of demo I am hard coding */ 
$userId = 1; 
$firstName = 'Balaji1'; 
$lastName = 'Vishwanath1'; 
try { 
    $userQuery = $pdo->prepare(" 
        UPDATE  
            `users` 
        SET 
            `first_name`    = :first_name, 
            `last_name`     = :last_name 
        WHERE 
            `id` = :user_id 
    "); 
    $userQuery->execute([ 
        ':first_name'   => $firstName, 
        ':last_name'    => $lastName, 
        ':user_id'      => $userId 
    ]); 
 
    /** If no records were updated then it will throw exception */ 
    if ($userQuery->rowCount() < 1) { 
        throw new Exception('No records updated.'); 
    } 
 
    echo 'Updated successfully.'; 
} catch (Exception $e) { 
    /** Handle all your errors here */ 
    exit($e->getMessage()); 
} 
 
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