How I can add atrribute to Laravel model collection? - sql

Question

I have Collection of Category.
with App\Category::all() I get:
ID | PARENT_ID | NAME | DEPTH'
1 | 0 | parent1 | 0
2 | 0 | parent2 | 0
3 | 1 | child1 | 1
4 | 2 | child2 | 1
How I can add custom atrribute (column or method results) to my collection?
The result I wanna get when I write etc: $categories=Category::with('childs');
ID| PARENT_ID | NAME | DEPTH' | CHILDS
1 | 0 | parent1 | 0 | {2 | 1 | child1 | 1 | NULL}
2 | 0 | parent2 | 0 | {3 | 2 | child2 | 1 | NULL}
3 | 1 | child1 | 1 | NULL
4 | 2 | child2 | 1 | NULL
I think you get the idea. I tried use Accessors & Mutators and I successfully added attribute with data etc.
$category->childs; // value should be {12 | 10 | name1 | 1 | NULL}
but I'm stuck because I can't pass data to method with queried data and return it back. I want to use one table, later I will add left and right columns to table to have tree database, now I'm just trying a little simpler - have parent and add children to it's collection

Answer 1

You should use model relationship to itself:
Category.php
<?php
namespace App;
use Illuminate\Database\Eloquent\Model;
class Category extends Model
{
protected $with = ['childs'];
public function childs()
{
return $this->hasMany(Category::class, 'parent_id');
}
}
CategoryController.php
public function index()
{
$categories = Category::all();
return $categories;
}
$categories will return result as you need:
[
{
"id": 1,
"parent_id": 0,
"name": "parent1",
"depth": 0,
"childs": [
{
"id": 3,
"parent_id": 1,
"name": "child1",
"depth": 0,
"childs": []
}
]
},
{
"id": 2,
"parent_id": 0,
"name": "parent2",
"depth": 0,
"childs": [
{
"id": 4,
"parent_id": 2,
"name": "child2",
"depth": 0,
"childs": []
}
]
},
{
"id": 3,
"parent_id": 1,
"name": "child1",
"depth": 0,
"childs": []
},
{
"id": 4,
"parent_id": 2,
"name": "child2",
"depth": 0,
"childs": []
}
]