Laravelでリレーションのあるテーブルが更新できない

Question

Laravelの勉強中でリレーションの処理で詰まっています。

やりたいこと

フォームから入力した値をもとに、drills、problems、categoriesの各テーブルを更新したい。

初回登録(create）は行えるのですが、同じ内容を更新(update）する場合に、どのように処理を書けばよいか分かりません。
createと同じ処理では単純にレコードが追加になってしまうため、更新対象とするレコードを指定する必要があるのだとは思うのですが・・・。

DB

• usersテーブルとdrillsテーブルは１対多
• drillsテーブルとproblemsテーブルは１対多
• drillsテーブルとcategoriesテーブルは1対1

で紐付いています。

users
+-------------+---------------------+------+-----+---------+----------------+
| Field       | Type                | Null | Key | Default | Extra          |
+-------------+---------------------+------+-----+---------+----------------+
| id          | bigint(20) unsigned | NO   | PRI | NULL    | auto_increment |
| description | varchar(255)        | NO   |     | NULL    |                |
| drill_id    | bigint(20) unsigned | YES  | MUL | NULL    |                |
| created_at  | timestamp           | YES  |     | NULL    |                |
| updated_at  | timestamp           | YES  |     | NULL    |                |
+-------------+---------------------+------+-----+---------+----------------+

drills
+------------+---------------------+------+-----+---------+----------------+
| Field      | Type                | Null | Key | Default | Extra          |
+------------+---------------------+------+-----+---------+----------------+
| id         | bigint(20) unsigned | NO   | PRI | NULL    | auto_increment |
| title      | varchar(255)        | NO   |     | NULL    |                |
| created_at | timestamp           | YES  |     | NULL    |                |
| updated_at | timestamp           | YES  |     | NULL    |                |
| user_id    | bigint(20) unsigned | NO   | MUL | NULL    |                |
+------------+---------------------+------+-----+---------+----------------+

problems
+-------------+---------------------+------+-----+---------+----------------+
| Field       | Type                | Null | Key | Default | Extra          |
+-------------+---------------------+------+-----+---------+----------------+
| id          | bigint(20) unsigned | NO   | PRI | NULL    | auto_increment |
| description | varchar(255)        | NO   |     | NULL    |                |
| drill_id    | bigint(20) unsigned | YES  | MUL | NULL    |                |
| created_at  | timestamp           | YES  |     | NULL    |                |
| updated_at  | timestamp           | YES  |     | NULL    |                |
+-------------+---------------------+------+-----+---------+----------------+

categories
+-------------+---------------------+------+-----+---------+----------------+
| Field       | Type                | Null | Key | Default | Extra          |
+-------------+---------------------+------+-----+---------+----------------+
| id          | bigint(20) unsigned | NO   | PRI | NULL    | auto_increment |
| description | varchar(255)        | NO   |     | NULL    |                |
| drill_id    | bigint(20) unsigned | YES  | MUL | NULL    |                |
| created_at  | timestamp           | YES  |     | NULL    |                |
| updated_at  | timestamp           | YES  |     | NULL    |                |
+-------------+---------------------+------+-----+---------+----------------+

モデル

<?php

namespace App;

use Illuminate\Contracts\Auth\MustVerifyEmail;
use Illuminate\Foundation\Auth\User as Authenticatable;
use Illuminate\Notifications\Notifiable;
use Illuminate\Database\Eloquent\Relations;

class User extends Authenticatable
{
    use Notifiable;

    protected $fillable = [
        'name', 'email', 'password',
    ];

    protected $hidden = [
        'password', 'remember_token',
    ];

    protected $casts = [
        'email_verified_at' => 'datetime',
    ];

    public function drills()
    {
        return $this->hasMany('App\Drill');
    }

    public function problems()
    {
        return $this->hasManyThrough('App\Problem', 'App\Drill');
    }

    public function category()
    {
        return $this->hasOneThrough('App\Category', 'App\Drill');
    }
}

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;

class Drill extends Model
{

    protected $guarded = ['id'];

    public function user()
    {
        return $this->belongsTo('App\User');
    }

    public function problems()
    {
        return $this->hasMany('App\Problem');
    }

    public function category()
    {
        return $this->hasOne('App\Category');
    }
}

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;

class Problem extends Model
{
    protected $guarded = ['id'];

    public function Drill()
    {
        return $this->belongsTo('App\Drill');
    }
}

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;

class Category extends Model
{
    protected $guarded = ['id'];

    public function Drill()
    {
        return $this->belongsTo('App\Drill');
    }
}

コントローラ

?php

namespace App\Http\Controllers;

use App\Category;
use App\Problem;
use Illuminate\Http\Request;
use App\Drill;
use Illuminate\Support\Facades\App;
use Illuminate\Support\Facades\Auth;

class DrillsController extends Controller
{
   public function create(Request $request)
    {
        $request->validate([
            'title' => 'required|string|max:255',
            'category_name' => 'required|string|max:255',
            'problem0' => 'required|string|max:255',
            'problem1' => 'string|nullable|max:255',
            'problem2' => 'string|nullable|max:255',
            'problem3' => 'string|nullable|max:255',
            'problem4' => 'string|nullable|max:255',
            'problem5' => 'string|nullable|max:255',
            'problem6' => 'string|nullable|max:255',
            'problem7' => 'string|nullable|max:255',
            'problem8' => 'string|nullable|max:255',
            'problem9' => 'string|nullable|max:255',
        ]);

        $problem_desc = [];
        $category_name = [];
        foreach ($request->all() as $key=>$value)
        {
            if(preg_match('/problem/',$key))
            {
                if($value !== null){

                    $problem_desc[] = ['description' => $value];
                }
            }
            if(preg_match('/category_name/', $key) && $value !== null)
            {
                $category_name = [ 'name' => $value];
            }
        }

        $drill = new Drill;
        
        Auth::user()->drills()->save($drill->fill($request->only(['title', 'user_id'])));
        $drill->problems()->createMany($problem_desc);
        $drill->category()->create($category_name);

        return redirect('/drills/new')->with('flash_message', __('Registered.'));
    }

    public function update(Request $request, $id)
    {
        if(!ctype_digit($id)){
            return redirect('/drills/new')->with('flash_message', __('Invalid operation was performed.'));
        }

        $request->validate([
            'title' => 'required|string|max:255',
            'category_name' => 'required|string|max:255',
            'problem0' => 'required|string|max:255',
            'problem1' => 'string|nullable|max:255',
            'problem2' => 'string|nullable|max:255',
            'problem3' => 'string|nullable|max:255',
            'problem4' => 'string|nullable|max:255',
            'problem5' => 'string|nullable|max:255',
            'problem6' => 'string|nullable|max:255',
            'problem7' => 'string|nullable|max:255',
            'problem8' => 'string|nullable|max:255',
            'problem9' => 'string|nullable|max:255',
        ]);

        $problem_desc = [];
        $category_name = [];
        foreach ($request->all() as $key=>$value)
        {
            if(preg_match('/problem/',$key))
            {
                if($value !== null){

                    $problem_desc[] = ['description' => $value];
                }
            }
            if(preg_match('/category_name/', $key) && $value !== null)
            {
                $category_name = [ 'name' => $value];
            }
        }

        $drill = new Drill;

        $drill = Auth::user()->drills()->find($id);
        Auth::user()->drills()->save($drill->fill($request->only(['title', 'user_id'])));

        /*
        フォームから入力した値をもとに、problemsテーブルとcategoriesテーブルを更新したい。
        createメソッドと同じ処理にした場合、レコードが追加されてしまう。
        */


    }

環境

PHP 7.2.5
Laravel 7.0

Answer 1

自己解決しました。
今回のテーブル設計では、対象のレコードをピンポイントで更新するのは難しいと判断し、対象レコードを一度削除した後に改めて値を挿入する形にしました。

以下、updateメソッドのみを抜粋したものです。

   public function update(InputDrillRequest $request, $id)
    {
        // GETパラメータが数字かどうかをチェックする
        if(!ctype_digit($id)){
            return redirect('/drills/new')->with('flash_message', __('Invalid operation was performed.'));
        }

        $problem_desc = [];
        $category_name = [];
        foreach ($request->all() as $key=>$value)
        {
            if(preg_match('/problem/',$key) && $value !== null)
            {
                $problem_desc[] = [
                    'description' => $value,
                    'form_num' => mb_substr($key,-1)
                ];

            }
            if(preg_match('/category_name/', $key) && $value !== null)
            {
                $category_name = [ 'name' => $value];
            }
        }

        $drill = Auth::user()->drills()->find($id);
        Auth::user()->drills()->save($drill->fill($request->only(['title', 'user_id'])));

        $drill = Drill::find($id);
        $drill->problems()->delete();
        $drill->problems()->createMany($problem_desc);

        $drill->category()->delete();
        $drill->category()->create($category_name);


        return redirect('/drills')->with('flash_message', __('Registered.'));
    }