How to get two arrays of obiects by one column

Question

Hi i have on table with categories with foreign key to herself where parent_id is the same that id in this table. I want to get two arrays of objects. First with categories where

parent_id=0

and second with subcategories. But I dont know how can I catch this subcategories. I have this:

$category= Category::where('parent_id', '=', 0)->get();
dd($category[0]['id']);
$subcategory= Category::where('parent_id', '=', (($category[0]['id']??)));

First $category shouild return me array of categories and second array with subcategories i need adjust id of each object of array $category to each subcategory array. Is it possible or there are other ways?

jedrzej.kurylo jedrzej.kurylo · Accepted Answer · 2016-08-01T14:25:55

If you define your model relations correctly you can get categories and their subcategories in a much nicer way.

First define the relations:

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

  public function subcategories() {

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

You can now get all parent categories with their subcategories the following way:

$parents = Category::whereParentId(0)->with('subcategories')->get();

This will give you list of all parent categories, each of them will have subcategories property that will store all subcategories. You can traverse them in the following way:

foreach ($parents as $parent) {
  printf("Parent category %s\n", $parent->name);

  foreach ($parent->subcategories as $subcategory) {
    printf("Subcategory %s\n", $subcategory->name);
  }
}

Small suggestion: make your parent_id nullable and store NULL for parent categories instead of 0, as 0 is not a correct category ID.

How to get two arrays of obiects by one column

1 Answers