autocde2.0/app/Models/Plan.php

<?php

namespace App\Models;

use App\Models\Scopes\CompanyScope;
use EloquentFilter\Filterable;
use Illuminate\Database\Eloquent\Factories\HasFactory;
use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Eloquent\SoftDeletes;

class Plan extends Model
{
    use HasFactory, Filterable,SoftDeletes;

    protected $fillable = [
        'title',
        'asset_id',
        'parent_id',
        'begin',
        'end',
        'description',
    ];

    protected static function booted()
    {
        parent::booted(); // TODO: Change the autogenerated stub

        static::addGlobalScope(new CompanyScope);
    }

    public function requirements()
    {
        return $this->hasMany(Requirement::class);
    }

    public function projects()
    {
        return $this->belongsToMany(Project::class, 'project_plan', 'plan_id', 'project_id');
    }

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

    public function asset(){
        return $this->belongsTo(Asset::class);
    }
}