Relationship HasManyThrough with Many to Many relationship

问题

Each Article belongs to many Categories. Each User has many Categories. I want to retrieve all the Articles which has the User’s Categories. For each of these relationships below I have my own pivot tables.

article_cat

id | articleID | categoryId

users_cats

id | user_details_id | categories_id

Relationships.

Articles.php

public function categories()
    {
        return $this->belongsToMany('App\Categories', 'article_categories', 'articleID', 'categoryID');
    }

UserDetails.php

 public function Categories(){
        return $this->belongsToMany('App\Categories', 'users_cats', 'user_details_id', 'categories_id');
    }

Categories.php

public function articles(){
    return $this->belongsToMany('App\Article', 'article_categories', 'categoryID', 'articleID');
}
public function UserDetails(){
    return $this->HasMany('App\UserDetails', 'users_cats', 'user_details_id', 'categories_id');
}

I have tried to use HasMany through but It doesn’t work with a many to many relationship as far as I can tell.

Currently (as a sort of “work around”) Ive been using this. Ive pulled up a list of the user's Categories and searching through all of ids and pulling the relevant Article and forming a collection from it in UserDetails.php

$user = self::find($this->id);
$user = $user->Categories;

        foreach ($user as $item) {
            foreach ($item->articles as $article)
            $article1[] = Article::find($article->id);
        }

        $articles = collect($article1)->sortByDesc('date')->unique();
        return $articles;

However I don’t think it will scale well with increasing data (its already producing over 1k queries with only 1000 articles, taking over 8 seconds to load).

Any ideas?

回答1:

You could use an IN query. Or a subquery.

Article::whereIn('id', $user->Categories::all->lists('id')->toArray() )



$category_id = $user->Categories::all->lists('id')->toArray();
Article::whereIn('id', function($query) use ($category_id){
   $query->select('categories_id')
     ->from(with(new Category)->getTable())
     ->whereIn('category_id', $categoryID )
})->get();

来源：https://stackoverflow.com/questions/42181700/relationship-hasmanythrough-with-many-to-many-relationship

标签

laravel

eloquent