Sum of a field with hasMany in cakephp

Question

I have two models in cakephp, Link and Vote.

I want to have the sum of the votes for every link in my Link model. Here is a print of my findAll function :

[1] => Array
    (
        [Link] => Array
            (
                [id] => 1
                [url] => http://www.google.com
                [date_added] => 2010-08-19 11:36:56
                [valid] => 1
            )

        [Vote] => Array
            (
                [0] => Array
                    (
                        [link_id] => 1
                        [user_id] => 0
                        [vote] => 3
                    )

                [1] => Array
                    (
                        [link_id] => 1
                        [user_id] => 4
                        [vote] => 4
                    )

            )

    )

What I would like to have is this (note the votes attribute) :

[1] => Array
    (
        [Link] => Array
            (
                [id] => 1
                [url] => http://www.google.com
                [date_added] => 2010-08-19 11:36:56
                [valid] => 1
                [votes] => 7
            )

        [Vote] => Array
            (
                [0] => Array
                    (
                        [link_id] => 1
                        [user_id] => 0
                        [vote] => 3
                    )

                [1] => Array
                    (
                        [link_id] => 1
                        [user_id] => 4
                        [vote] => 4
                    )

            )

    )

But I have no idea where I'm supposed to do the SUM of the votes.

Answer 1

You can create a virtual field "votes" in your Link model. http://book.cakephp.org/view/1608/Virtual-fields

var $virtualFields = array(    
    'votes' => 'COUNT ...'
);