Trying to contain a field that uses UNIX_TIMESTAMP - cakephp

Question

I'm trying to convert the updated datetime column to a number. So I did this in my Containable behavior.
$this->paginate = array(
'limit'=>1,
'fields'=>array(
'id',
),
'contain'=>array(
'Image'=>array('fields'=>array(
'id',
'UNIX_TIMESTAMP(Image.updated) AS `rev`',
))
)
);
I get this data from Paginator
Array
(
[0] => Array
(
[Receipt] => Array
(
[id] => 19938
)
[Image] => Array
(
[0] => Array
(
[id] => 18143
[receipt_id] => 19938
[Image] => Array
(
[0] => Array
(
[rev] => 1357872726
)
)
)
[1] => Array
(
[id] => 18144
[receipt_id] => 19938
[Image] => Array
(
[0] => Array
(
[rev] => 1357872728
)
)
)
)
)
)
For some reason Image is nested twice for each record. If I remove the UNIT_TIMESTAMP it gets the data correctly.
$this->paginate = array(
'limit'=>1,
'fields'=>array(
'id',
),
'contain'=>array(
'Image'=>array('fields'=>array(
'id',
'updated',
))
)
);
Output
Array
(
[0] => Array
(
[Receipt] => Array
(
[id] => 19938
)
[Image] => Array
(
[0] => Array
(
[id] => 18143
[updated] => 2013-01-10 21:52:06
[receipt_id] => 19938
)
[1] => Array
(
[id] => 18144
[updated] => 2013-01-10 21:52:08
[receipt_id] => 19938
)
)
)
)
Any idea why Cake is going this when I add an expression to a field?

Answer 1

You can try using virtual fields:
public function __construct($id = false, $table = null, $ds = null) {
parent::__construct($id, $table, $ds);
$this->virtualFields['name'] = sprintf(
'UNIX_TIMESTAMP(%s.updated) AS %s.rev', $this->alias, $this->alias
);
}
Not sure if my notation is right, give it a try, I haven't tested it.