CakePHP: joins inside contain - php

Question

As the title says, I'm having troubles with joins in my find-query, with errors appearing like:
preg_match() expects parameter 2 to be string, array given [CORE/cake/libs/model/behaviors/containable.php, line 301]
I've tried adding joins to the array over there, but it didn't change anything.
These are the options I'm passing to the find method.
$options = array(
'contain' => array(
'Answer' => array(
'conditions' => array('Answer.type' => 'answer'),
'joins' => array(
$this->votesJoin()
),
'Comment' => array(
'conditions' => array('Comment.type' => 'comment'),
'joins' => array(
$this->votesJoin()
)
)
),
'Comment' => array(
'conditions' => array('Comment.type' => 'comment'),
'joins' => array(
$this->votesJoin()
)
),
'User',
'Tag' => array()
),
'joins' => array(
$this->votesJoin()
),
'conditions' => array(
'Question.id' => $id
)
);
return $this->find('first', $options);
with votesJoin() returning the following array.
(
[table] => (SELECT Vote.node_id, SUM(value) as total FROM votes AS `Vote` WHERE 1 = 1 GROUP BY `Vote`.`node_id` )
[alias] => Vote
[conditions] => Vote.node_id = Question.id
)
What I'm trying to do:
Each user can up/downvote a node (question/answer/comment). With the join I'm trying to add the sum of those votes.
database http://github.com/navale/QA/wiki/img/datamodel.png

Answer 1

You should use "joins" only for things that can't be done with Cake model relationship and Containable. I don't know the details of your database, but I think the find operation can be simplified. Why don't you post the schema for these tables on here?
try this:
$options = array(
'contain' => array(
'Answer' => array(
'conditions' => array('Answer.type' => 'answer'),
'Vote' => array(
'fields' => array('SUM(Vote.value)'),
'group' => array('Vote.parent_id')
),
'Comment' => array(
'conditions' => array('Comment.type' => 'comment'),
'Vote' => array(
'fields' => array('SUM(Vote.value)'),
'group' => array('Vote.parent_id')
)
)
),
'Comment' => array(
'conditions' => array('Comment.type' => 'comment'),
'Vote' => array(
'fields' => array('SUM(Vote.value)'),
'group' => array('Vote.parent_id')
)
),
'User',
'Tag' => array()
),
'conditions' => array(
'Question.id' => $id
)
);
You get the Vote sum value for each answer, comment, and comment for answer. (You might need to add 'hasMany' Vote in the Node model if you haven't done that yet)
If instead you want to get one single total sum of Vote for the question, then I'd suggest:
get the list of the answers and comments of the question:
$lvl1 = find('list','fields'=>array('id'),'conditions'=>array('Node.parent_id'=>$id))
then get list of the comments of the answers
$lvl2 = find('list','fields'=>array('id'),'conditions'=>array('Node.parent_id'=>$lvl1))
then just combine the 2 array then do a sum over that.