Cakephp: associations of associations in "fields" - cakephp

Question

a post has a user (belongsTo) and a user has a profile (hasOne). Normally everything works: I can access from Post to User and from User to Profile.
From Post, all works using a generic Find. The result is more or less this (I deleted some keys, just for example):
array(
'Post' => array(
'id' => '1',
'category_id' => '1',
'user_id' => '1',
'title' => 'Example',
'text' => '',
),
'User' => array(
'password' => '*****',
'id' => '1',
'group_id' => '1',
'username' => 'mirko',
'status' => 'active',
'Profile' => array(
'id' => '1',
'user_id' => '1',
'first_name' => 'Mirko',
'last_name' => 'Pagliai',
),
)
)
The problem comes when I use "fields", when I want to extract only a few fields.
For example, this works:
'fields' => array('id', 'title', 'User.id')
and the result is:
array(
'Post' => array(
'id' => '1',
'title' => 'Articolo di prova :-)'
),
'User' => array(
'id' => '1'
)
)
But I don't understand, always using "fields", how to access Profile.
These don'yt work:
'fields' => array('id', 'title', 'User.id', 'Profile.id')
'fields' => array('id', 'title', 'User.id', 'User.Profile.id')
I always get this error "Error: SQLSTATE[42S22]: Column not found: 1054 Unknown column 'User.Profile.id' in 'field list'".
What's wrong? Thanks.
EDIT:
I'm not using the Containable behavior. Maybe is this the problem? Is it essential in this case?
An example, using paginate:
$this->paginate = array(
'conditions' => $conditions,
'fields' => array('id', 'title', 'User.id', 'Profile.id'),
'limit' => 10,
'recursive' => 2,
);
EDIT2:
thanks to #Hoff, I am close to the solution. But there is still something wrong (and Containable is very useful!).
In AppModel.php I added:
...
class AppModel extends Model {
public $actsAs = array('Containable');
public $recursive = -1;
...
But this doesn't work:
$this->paginate = array(
'conditions' => $conditions,
'contain' => array(
'User' => array(
'fields' => array('id'),
'Profile' => array(
'fields' => array('id', 'full_name'),
),
),
'Category' => array(
'fields' => 'title',
),
),
'fields' => array('id', 'user_id', 'category_id', 'title', 'created', 'modified', 'published'),
'limit' => 10,
);
Cause I get:
array(
(int) 0 => array(
'Post' => array(
'id' => '1',
'user_id' => '1',
'category_id' => '1',
'title' => 'Articolo di prova :-)',
'created' => '2012-06-21 18:46:00',
'modified' => '0000-00-00 00:00:00',
'published' => true
),
'Category' => array(
'title' => 'prova',
'id' => '1'
),
'User' => array(
'id' => '1'
)
)
)
but if I add any field to User (email, username, password, etc.), this works:
'User' => array(
'fields' => array('id', 'username'),
'Profile' => array(
'fields' => array('id', 'full_name'),
),
),
And I get:
array(
(int) 0 => array(
'Post' => array(
'id' => '1',
'user_id' => '1',
'category_id' => '1',
'title' => 'Articolo di prova :-)',
'created' => '2012-06-21 18:46:00',
'modified' => '0000-00-00 00:00:00',
'published' => true
),
'Category' => array(
'title' => 'prova',
'id' => '1'
),
'User' => array(
'id' => '1',
'username' => 'mirko',
'Profile' => array(
'id' => '1',
'full_name' => 'Mirko Pagliai'
)
)
)
)

Answer 1

Instead of using the 'recursive' key, I highly suggest using the containable behavior. The documentation on the behavior can be found here. I would suggest applying the behavior in your AppModel so you don't need to add it to all your models. In Model/AppModel.php:
App::uses('Model', 'Model');
class AppModel extends Model {
public $actsAs = array('Containable');
public $recursive = -1;
}
Then, for your pagination:
$this->paginate = array(
'conditions' => $conditions,
'fields' => array('id', 'title'),
'limit' => 10,
'contain' => array(
'User' => array(
'fields' => array('id'),
'Profile' => array(
'fields' => array('id')
)
)
)
);