Question

I have two models, Post and Tag which are set up in a HABTM relationship like so:

class Post extends AppModel {
    public $hasAndBelongsToMany = array('Tag');
}

class Tag extends AppModel {    
    public $hasAndBelongsToMany = array('Post');
}

When editing a post, I would like to display all of the tags belonging to this post in an input box.

Right now I have this in my posts controller:

$this->set('tags', $this->Post->Tag->find('list'));

But for some reason it’s returning every tag that’s in the tags table, rather than returning only the ones belonging to that post.

How can I modify this so it only retrieves tags that belong to the post I’m editing?

Answer 1

The way that you use the find() function means you want all rows of tags table.

in your models :

class Post extends AppModel {


/**
 * @see Model::$actsAs
 */
    public $actsAs = array(
        'Containable',
    );


        public $hasAndBelongsToMany = array('Tag');
}

class Tag extends AppModel {    

/**
 * @see Model::$actsAs
 */
    public $actsAs = array(
        'Containable',
    );

    public $hasAndBelongsToMany = array('Post');
}

You should use find function this way:

$postWithTag = $this->Post->find('first', array('conditions' => array('Post.id' => $post_id),'contain'=>array('Tag')));

it returns Post with its tags.

if you want only tags without post you should place belongsTo relation in PostTag model:

class PostTag extends AppModel {    

/**
 * @see Model::$belongsTo
 */
    public $belongsTo = array(
        'Post','Tag'
    );
}

then use the find function this way:

class PostController extends AppController {

/**
 * @see Controller::$uses
 */
    public $uses = array(
        'Post', 'PostTag'
    );

    public function post(){

          /**
           * Your code
           */
          $tags = $this->PostTag->find('all', array('conditions' => array('PostTag.post_id' => $post_id)));
          $this->set('tags',$tags);
    }