Laravel Data Deletion

Question

How can I prevent data deletion if the data of one data-table is used in another data-table as foreign key in Laravel? This is a controller from where I have to delete data.

<?php

namespace App\Http\Controllers;

use Illuminate\Http\Request;
use App\Models\Theme;

class ThemeController extends Controller
{

    public function destroy($id)

        Theme::destroy($id);
        return redirect()->route('theme.index')->withFlashSuccess('Theme profile is deleted successfully.');
    }
}

How can I apply a condition to stop the deletion the data in this controller, if this controller data is used in another controller?

Answer 1

Copy and replace with your current function

  public function destroy($id)
{
    $foreignKeyCheck = DB::table('general_agreement_theme ')
            ->where('theme_id' ,$id)->get();

    if($foreignKeyCheck->isEmpty())
    {
        Theme::destroy($id);
        return redirect()->route('theme.index')->withFlashSuccess('Theme profile is deleted successfully.');
    }else{
        return redirect()->route('theme.index')->withFlashSuccess('Theme profile is deleted successfully.');
    }
        
}

And don't forget to import

use Illuminate\Support\Facades\DB;

at the top of the controller.