Question

I’m using the cakephp framework to develop an application and I’m running into some trouble understanding the associations between these models fully. Below you can see the four models along with their relative database fields.

User
 id

Profile
 id
 user_id

Post (A blog post on the users profile)
 id
 profile_id
 topic_id

Topic (A topic for a blog post)
 id
 name

Here are the associations as they currently stand:

User
 hasOne: Profile

Profile
 hasMany: Posts

Post
 belongsTo: Topic, Profile

Now my problem. I am unsure if you have to define associations like User hasMany Posts or if it’s already assumed because User hasOne Profile and Profile hasMany Posts. My other problem is defining the relationship between a post and its topic.

• A profile can have unlimited posts
• A post must be associated with a profile
• A post can only have one topic
• The topic table contains a list of all topics
• A post does not NEED a topic

Given these criteria how should my associations look? All the research I’ve done on associations only shows simple examples.

I’m using CakePHP version 2.1.3

Thanks for any and all help and/or advice in advance

Answer 1

You can recursively find associations of associations, or even better, use Containable.

In the model (I recommend putting it in AppModel, since I find myself using Containable for everything):

class AppModel extends Model {
    public $actsAs = array('Containable');
    ...
}

Then when you call read (or find, or paginate) for User, most likely in your controller, do this:

$this->User->contain(array(
    'Profile' => array(
        'Post'
    )
));
$data = $this->User->read();
$set('user',$data);

If you set that data to your view, you can then access the id of one of the posts from $user['Profile']['Post'][0]['id'].

Now for your next question, you can have conditional associations.

public $hasMany = array(
    'Topic' => array(
        'className' => 'Topic',
        'conditions' => 'Post.topic_id IS NOT NULL'
    )
)