[FIXED] CakePHP 3 join table associations

Issue

Alright, I have some issues understanding how the associations are working, particularly belongsTo here is my setup:

Articles can have multiple Categories
Categories can belong to multiple Articles

so in my database i have 3 tables: articles, categories and a join table articles_categories

Table/ArticlesTable.php:

public function initialize(array $config)
{
    $this->addBehavior('Timestamp');
    $this->table('articles');
    $this->belongsTo('Users');
    $this->belongsToMany('Categories', [
        'through' => 'ArticlesCategories',
        'alias' => 'Categories',
        'foreignKey' => 'article_id',
        'joinTable' => 'articles_categories',
        'targetForeignKey' => 'category_id'

    ]);

}

Table/CategoriesTable.php:

public function initialize(array $config)
{
    $this->table('categories');
    $this->displayField('name');
    $this->primaryKey('id');
    $this->addBehavior('Timestamp');
    $this->belongsToMany('Articles', [
        'through' => 'ArticlesCategories',
        'alias' => 'Articles',
        'foreignKey' => 'category_id',
        'joinTable' => 'articles_categories',
        'targetForeignKey' => 'article_id'
    ]);
}

Table/ArticlesCategoriesTable.php:

public function initialize(array $config)
{
    $this->belongsTo('Articles');
    $this->belongsTo('Categories');
}

Now inside in the view action CategoriesController.php i can overview a particular category and i need to retrieve some articles related to that category. What is the right way to do such a thing? Here is what i have:

public function view($id = null)
{
    $category = $this->Categories->find('all',['limit'=>1])->where(['Categories.id' => $id])->contain(['Articles']);
    $this->set(['category'=> $category]);
}

It kinda does the job but I'd also need to be able to limit the number of related articles..

Solution

you can modify the query object used to load the associated models:

$category = $this->Categories->find('all',['limit'=>1])
    ->where(['Categories.id' => $id])
    ->contain(['Articles' => function($q) {
        $q->limit(10);  
        return $q;
    }    
]);

edit: or you can do

$category = $this->Categories->get($id, 
[
    'contain' => [
        'Articles' => function($q) {
            $q->limit(10);  
            return $q;
    }    
]);

or maybe if you want the Articles without the Category data you can use matching

$articles = $this->Categories->Articles->find()
    ->matching('Categories', function ($q) use $id{
        return $q->where(['id' => $id])
    ->limit(10);

I did not tested the last one but I think something like that should work

But as you can see the complexity is more o less the same

Answered By - arilia