parent id for category and subcategory - php

Question

I use L8 And I have a category table ,it has parent_id for my subcategories
categories table
Category model
categoryController
SubCategoryController
categories.blade
sub_categories.blade
In my subcategory-index.blade.php I want to show categories but I just can show them with their id (parent id)
I don't know how to show categories title instead of their id.
I have this migration for categories table :
public function up()
{
Schema::dropIfExists('categories');
Schema::create('categories', function (Blueprint $table) {
$table->id();
$table->unsignedBigInteger('parent_id')->default(123);
$table->string('title');
$table->longText('description');
$table->tinyInteger('status')->comment('status is 1 when a category is active and it is 0 otherwise.')->nullable();
$table->rememberToken();
$table->softDeletes();
$table->timestamps();
});
}
and this is my category model :
class Category extends Model
{
use HasFactory;
protected $fillable = [
'parent_id','title' , 'description', 'status',
];
public function children(){
return $this->hasMany(Category::class , 'parent_id');
}
public function post(){
return $this->hasMany(Post::class);
}
}
And my subcategory controller :
...
public function index()
{
$parent_id = Category::with('parent_id')->get();
$subcategories = Category::where('parent_id' ,'!=', 123)->get();
return view('admin.subcategories.subcategories-index' , compact('subcategories'));
}
...
And the part for show subcategory title in category-index.blade.php :
<table class="table table-bordered">
<tr>
<th>#</th>
<th>id</th>
<th>title</th>
<th>category</th>
<th>status</th>
<th>operation</th>
</tr>
#foreach($subcategories as $subcategory )
<tr>
<td>{{ $loop->iteration }}</td>
<td>{{ $subcategory['id'] }}</td>
<td>{{ $subcategory['title'] }}</td>
<td>{{ $subcategory['parent_id']}}</td>
<td>
#if($subcategory['status']==0 or $subcategory['status']==NULL)
inactive
#else
active
#endif
</td>
<td>
<form method="POST" action="{{ route('subcategory.destroy',$subcategory->id) }}">
<a class="btn btn-info" href="{{ route('subcategory.show' , $subcategory->id) }}">show</a>
<a class="btn btn-primary" href="{{ route('subcategory.edit' , $subcategory->id) }}">edit</a>
#csrf
#method('DELETE')
<button type="submit" class="btn btn-danger"> delete</button>
</form>
</td>
</tr>
#endforeach
</table>
Thanks for telling me what to do :>

Answer 1

To get subcategories
$sub_categories = Category::whereNotNull('parent_id')->get();
To get sub-categories with parent
$sub_categories_with_parent = Category::with('parent')->whereNotNull('parent_id')->get();
To fetch categories
$categories = Category::whereNull('parent_id')->get();
To fetch categories with children
$categories_with_childern = Category::with('children')->whereNull('parent_id')->get();
You might have to redefine your relations as well:
public function parent()
{
return $this->belongsTo(Category::class);
}
public function children()
{
return $this->hasMany(Category::class , 'parent_id');
}
In migration define relation as well
$table->foreign('parent_id')->references('id')->on('categories')->onUpdate('cascade')->onDelete('cascade');
Make parent field nullable
$table->unsignedBigInteger('parent_id')->nullable()->default(123);

Answer 2

The line down below is incorrect. Because with() is used to get relational data and parent_id is not a relation name.
$parent_id = Category::with('parent_id')->get();
If your route contains the id or slug of the category, you can use it, but I think it doesn't, because your index function doesn't accept any route parameter. So I assume you are trying to fetch all categories and subcategories. But in this case, the second line of the index function doesn't make sense at all.
If you want to all categories:
$categories = Category::where('parent_id', null)->with('children')->get();
I see you use 123 for top-level categories, and it looks high enough. But nullable is a better practice for that purpose.
If you need a specific category and its subcategories:
// web.php
Route::get('category/{slug}', [CategoryController::class, 'index']);
// CategoryConteroller.php
public function index($slug)
{
$category = Category::where('slug', $slug)->with('children')->get();
}