CourseWork/app/Models/Subject.php

<?php

namespace App\Models;

use Illuminate\Contracts\Database\Eloquent\Builder;
use Illuminate\Database\Eloquent\Factories\HasFactory;
use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Eloquent\Relations\BelongsToMany;
use Illuminate\Database\Eloquent\Relations\HasMany;
use Illuminate\Database\Eloquent\Relations\MorphOne;

class Subject extends Model
{
    use HasFactory;

    protected $fillable = [
        'name',
    ];

    public function grades(): BelongsToMany
    {
        return $this->belongsToMany(Grade::class);
    }

    public function teachers(): BelongsToMany
    {
        return $this->belongsToMany(Teacher::class);
    }

    public function students(): BelongsToMany
    {
        return $this->belongsToMany(Student::class)->using(Score::class);
    }

    public function lessons(): HasMany
    {
        return $this->hasMany(Lesson::class);
    }

    public function scopeFilter(Builder $query): void
    {
        $name = request('name');

        $query->when($name, function (Builder $query, $name) {
            $query->whereRaw('name ilike ?', ["$name%"]);
        });
    }

    public function user(): MorphOne
    {
        return $this->morphOne(User::class, 'userable');
    }
}