Article.php

<?php
# /app/Model/Article.php
class Article extends AppModel
{
  public $hasMany = array(
    'Comment'
  );
  public $validate = array(
    'title' => array(
       'rule' => array('notEmpty'),
       'required' => true,
       'allowEmpty' => false,
       'message' => 'inserire un titolo'
    )
  );
}