Check if category belongs to post - php

Question

Hello I'm trying to make script that show all categories and if category belongs to post this category should be checked with checkbox. My script wont works could you help me please. It shows only one checked category when have to shows two.
Controller Category model:
class Category extends Eloquent {
protected $table= "categories";
public function posts(){
return $this->belongsToMany('Post');
}
}
Post model
class Post extends Eloquent {
protected $table = 'posts';
public function categories(){
return $this->belongsToMany('Category');
}
}
catRelation:
[{"id":"45","post_id":"132","category_id":"1","created_at":"2014-12-26 20:32:41","updated_at":"2014-12-26 20:32:41"},{"id":"46","post_id":"132","category_id":"3","created_at":"2014-12-26 20:32:41","updated_at":"2014-12-26 20:32:41"}]
all categories: [{"id":"1","name":"Laravel","slug":"laravel","created_at":"-0001-11-30 00:00:00","updated_at":"-0001-11-30 00:00:00"},{"id":"3","name":"PHP","slug":"php","created_at":"-0001-11-30 00:00:00","updated_at":"-0001-11-30 00:00:00"}]

Answer 1

A category shouldn't ever belong to a post, but rather a post should belong to a category.
I assume catRelation is your pivot table. It's worth nothing that you need neither id, created_at or updated_at for this.
Example models:
class Post extends Eloquent
{
protected $table = 'posts';
public function category()
{
return $this->belongsToMany('Category', 'catRelation', 'category_id');
}
}
class Category extends Eloquent
{
protected $table = 'categories';
public function post()
{
return $this->belongsToMany('Post', 'catRelation', 'post_id');
}
}
Note: I may have got the final arguments in belongsToMany the wrong way around.