John Davidson

Message:

i have category table, and sub categories also in same table... if some category have null parent_id its top node category.
table basic fields like this:

---------------------

|id |name |parent_id|

---------------------

I just need to get all childs ids in minimum quarry execution:
eg:

Category::find(2)->allChildIds(); //result like [3,4,6,10,....]

i have this relationship added:

  public function parent(){

        return $this->belongsTo(Category::class);

    }



    public function childs(){

        return $this->hasMany(Category::class,'parent_id');

    }

thank you

---

My Answer:
You can achieve this by creating a recursive function in your Category model. Here's an example of how you can do this:

php
class Category extends Model
{
public function parent(){
return $this->belongsTo(Category::class);
}

public function childs(){
return $this->hasMany(Category::class,'parent_id');
}

public function allChildIds()
{
$childIds = [];

$this->getChildIds($this, $childIds);

return $childIds;
}

private function getChildIds($category, &$childIds)
{
foreach ($category->childs as $child) {
$childIds[] = $child->id;
$this->getChildIds($child, $childIds);
}
}
}


Now you can use the `allChildIds()` method to get all child ids of a specific category:

php
$childIds = Category::find(2)->allChildIds();


This will return an array of all child ids of the category with id 2.