Laravel 5：如何从某个类别（包括所有子类别）获取所有广告

Question

I have the following models and relations

class Advert extends Model
{
    public function category() {
        return $this->belongsTo('App\Category');
    }
}

class Category extends Model
{

    public function parent() {
        return $this->belongsTo('App\Category', 'category_id','id');
    }

    public function children() {
        return $this->hasMany('App\Category', 'category_id');
    }

    public function adverts() {
        return $this->hasMany('App\Advert');
    }
}

I have table with adverts who belong to a category ... The advert's category can be a subcategory of another category ... Subcategory level is max 4. How can i retrieve all the adverts from all subcategories through the main root category it belongs.

For example

 <ul> <li>Smartphones <ul> <li>Android <ul> <li>Samsung</li> <li>Huawei</li> <li>LG</li> <li>Meizu</li> <li>Acer</li> </ul> </li> <li>Apple <ul> <li>iPhone 5</li> <li>iPhone 6</li> <li>iPhone X</li> </ul> </li> </ul> </li> </ul> 

How can i get all adverts from all subcategories for example if i click on Smartphones ... Do i have to iterate through each level or there is an easier solution with relations...

Thanks

Answer 1

you can make relations recursive

class Advert extends Model
{
    public function category() {
        return $this->belongsTo('App\Category');
    }
}

class Category extends Model
{

    public function parent() {
        return $this->belongsTo('App\Category', 'category_id','id');
    }

    public function parentRecursive()
    {
        return $this->parent()->with('parentRecursive');
    }



    public function children() {
        return $this->hasMany('App\Category', 'category_id');
    }

    public function childrenRecursive()
    {
        return $this->children()->with('childrenRecursive');

    }

    public function adverts() {
        return $this->hasMany('App\Advert');
    }
}

for getting adverts with recursive results

$adverts = Advert::with('Category')
    ->with('Category.childrenRecursive')->whereNull('Category.parent')->get();

Answer 2

Try to use nested sets package. It is awesome and easily do this work.