How can this association be set up? - php

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'
)
)

Answer 2

I think everything looks fine
Your assumption is correct you dont have to define the User / Post relationship. Users dont have many Posts, Profiles do. You could store the user_id on the Post rather than profile_id to make thing a bit more intuitive but thats up to you.
Topic hasMany Post and you are done. The topic/post conditions you describe can be controlled via the forms and before saves on the model. For example 'A post must be associated with a profile', well at the point you save the post you add in the profile_id based on session info of the logged in user.