Laravelで作った図書館の貸し出しテーブルと本テーブルのリレーションの設定をしてビューファイルで表示をしたい

Question

前提・実現したいこと

表題の通りです。
ビューで貸し出しテーブルにリレーションしたusersテーブルのnameとbooksテーブルのtitleを表示させたいです。そのうえで貸し出しテーブルのreturn_dateがnullの値を抽出したいです。
ですがリレーション先へのアクセスができなくて詰まっています。

発生している問題・エラーメッセージ

Trying to get property 'title' of non-object

dd(&datas)をしてみたところ

Illuminate\Database\Eloquent\Collection {#310 ▼
  #items: array:1 [▼
    0 => App\Models\Lending {#312 ▼
      #table: "lendings"
      #fillable: array:5 [▼
        0 => "user_id"
        1 => "book_id"
        2 => "lent_date"
        3 => "return_date"
        4 => "status"
      ]
      +timestamps: false
      #connection: "sqlite"
      #primaryKey: "id"
      #keyType: "int"
      +incrementing: true
      #with: []
      #withCount: []
      +preventsLazyLoading: false
      #perPage: 15
      +exists: true
      +wasRecentlyCreated: false
      #attributes: array:6 [▼
        "id" => "2"
        "user_id" => "2"
        "book_id" => "3"
        "lent_date" => "2021-6-30"
        "return_date" => null
        "status" => "0"
      ]
      #original: array:6 [▼
        "id" => "2"
        "user_id" => "2"
        "book_id" => "3"
        "lent_date" => "2021-6-30"
        "return_date" => null
        "status" => "0"
      ]
      #changes: []
      #casts: []
      #classCastCache: []
      #dates: []
      #dateFormat: null
      #appends: []
      #dispatchesEvents: []
      #observables: []
      #relations: []
      #touches: []
      #hidden: []
      #visible: []
      #guarded: array:1 [▼
        0 => "*"
      ]
    }
  ]
}

該当のソースコード

###マイグレーションファイル

//database/migration/create_users_table
<?php

use Illuminate\Database\Migrations\Migration;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Support\Facades\Schema;

class CreateUsersTable extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        Schema::create('users', function (Blueprint $table) {
            $table->increments('id');
            $table->string('name');
            $table->string('email')->unique();
            $table->timestamp('email_verified_at')->nullable();
            $table->string('password');
        });
    }

    /**
     * Reverse the migrations.
     *
     * @return void
     */
    public function down()
    {
        Schema::dropIfExists('users');
    }
}

// database/migration/create_books_table
<?php

use Illuminate\Database\Migrations\Migration;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Support\Facades\Schema;

class CreateBooksTable extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        Schema::create('books', function (Blueprint $table) {
            $table->increments('id');
            $table->string('title');
        });
    }

    /**
     * Reverse the migrations.
     *
     * @return void
     */
    public function down()
    {
        Schema::dropIfExists('books');
    }
}

// database/migration/create_lendings_table
<?php

use Illuminate\Database\Migrations\Migration;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Support\Facades\Schema;

class CreateLendingsTable extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        Schema::create('lendings', function (Blueprint $table) {
            $table->increments('id');
            $table->integer('user_id');
            $table->integer('book_id');
            $table->timestamp('lent_date');
            $table->timestamp('return_date')->nullable();
            $table->boolean('status');

            $table->foreign('user_id')
                ->references('id')
                ->on('users')
                ->onDelete('cascade');
                
            $table->foreign('book_id')
                ->references('id')
                ->on('books')
                ->onDelete('cascade');
        });
    }

    /**
     * Reverse the migrations.
     *
     * @return void
     */
    public function down()
    {
        Schema::dropIfExists('lendings');
    }
}

モデル

// App/Model/Book

<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Model;
use App\Models\Lending;

class Book extends Model
{
    protected $table = 'books';

    protected $fillable = ['title'];

    public $timestamps = false;

    public function lendings()
    {
        return $this->hasMany(Lending::class, 'book_id');
    }

    public function getData()
    {
        $datas = [
            'id' => $this->id,
            'title' => $this->title,
        ];
        return $datas;
    }
}

// App/Models/User
<?php

namespace App\Models;

use Illuminate\Contracts\Auth\MustVerifyEmail;
use Illuminate\Database\Eloquent\Factories\HasFactory;
use Illuminate\Foundation\Auth\User as Authenticatable;
use Illuminate\Notifications\Notifiable;
use App\Models\Lending;

class User extends Authenticatable
{
    use HasFactory, Notifiable;

    /**
     * The attributes that are mass assignable.
     *
     * @var array
     */
    protected $fillable = [
        'name',
        'email',
        'password',
    ];

    /**
     * The attributes that should be hidden for arrays.
     *
     * @var array
     */
    protected $hidden = [
        'password',
        'remember_token',
    ];

    /**
     * The attributes that should be cast to native types.
     *
     * @var array
     */
    protected $casts = [
        'email_verified_at' => 'datetime',
    ];

    public $timestamps = false;

    public function lendings()
    {
        return $this->hasMany(Lending::class);
    }
}

// App/Models/Lending
<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Model;
use App\Models\User;
use App\Models\Book;

class Lending extends Model
{
    protected $table = 'lendings';

    protected $fillable = [
        "user_id",
        'book_id',
        'lent_date',
        'return_date',
        'status',
    ];

    public $timestamps = false;

    public function user()
    {
        return $this->belongsTo(User::class, 'id');
    }

    public function book()
    {
        return $this->belongsTo(Book::class, 'id');
    }
   

    public function getData()
    {
        $datas = [
            'id' => $this->id,
            'user_id' => $this->user_id,
            'book_id' => $this->book_id,
            'lent_date' => $this->lent_date,
            'return_date' => $this->status,
        ];
        return $datas;
    }
}

シーダー

// database/seeder/UserSeeder
<?php

namespace Database\Seeders;

use Illuminate\Database\Seeder;
use Illuminate\Support\Facades\DB;
use Illuminate\Support\Facades\Hash;

class UserSeeder extends Seeder
{
    /**
     * Run the database seeds.
     *
     * @return void
     */
    public function run()
    {
        for ($i = 1; $i <= 10; $i++) {
            DB::table('users')->insert([
                'id' => $i,
                'name' => 'user' . $i,
                'email' => 'email' . $i . '@gmail.com',
                'password' => Hash::make('password'),
            ]);
        }
    }
}

//database/seeder/BookSeeder
<?php

namespace Database\Seeders;

use Illuminate\Database\Seeder;
use Illuminate\Support\Facades\DB;

class BookSeeder extends Seeder
{
    /**
     * Run the database seeds.
     *
     * @return void
     */
    public function run()
    {
        for ($i = 1; $i <= 10; $i++) {
            DB::table('books')->insert([
                'title' => 'title' . $i,
            ]);
        }
    }
}

// database/seeder/LendingSeeder
<?php

namespace Database\Seeders;

use Illuminate\Support\Facades\DB;
use Illuminate\Database\Seeder;

class LendingSeeder extends Seeder
{
    /**
     * Run the database seeds.
     *
     * @return void
     */
    public function run()
    {
            DB::table('lendings')->insert([
                'user_id' => '1',
                'book_id' => '2',
                'lent_date' => '2021-6-30',
                'return_date' => '2021-7-4',
                'status' => '0',
            ]);

            DB::table('lendings')->insert([
                'user_id' => '2',
                'book_id' => '3',
                'lent_date' => '2021-6-30',
                'return_date' => null,
                'status' => '0',
            ]);
    }
}

コントローラ

// App/Http/Controller/LendingController
<?php

namespace App\Http\Controllers;

use Illuminate\Http\Request;
use App\Models\Lending;
use App\Models\Book;

class LendingController extends Controller
{
    // 貸出中の本を表示
    public function index()
    {
        $datas = Lending::whereNull('return_date')->get();
        return view('index', ['datas' => $datas]);
    }
}

ビュー

@extends('layouts.app')

@section('content')
    @foreach($datas as $data)
        id{{ $data->id }}
        本の名前{{ $data->books->title }}
        借りての名前{{ $data->users->name }}
        貸し出し日{{ $data->lent_date }}
        <br>
    @endforeach
@endsection

補足情報（FW/ツールのバージョンなど）

Laravel 8.49.2

Answer 1

mikkameさんのコメントをまとめてcloseします。

// LendingController
class LendingController extends Controller
{
    // 貸出中の本を表示
    public function index()
    {
        $datas = Lending::whereNull('return_date')
            ->with('book')
            ->with('user')
            ->get();
        return view('index', ['datas' => $datas]);
    }
}

// index.blade.php
@extends('layouts.app')

@section('content')
    @foreach($datas as $data)
        id{{ $data->id }}
        title{{ $data->book->title }}
        name{{ $data->user->name }}
        lent_date{{ $data->lent_date }}
        <br>
    @endforeach
@endsection

Answer 2

Lending::where('return_date', null)->get();

ではなく
Lending::whereNull('return_date')->get();
ですね

Comments

[n18marron]

whereNullに変更してddしてみたところ、relationのところが[]だけなんですが、この状態ってリレーションはちゃんと設定されているでしょうか

[mikkame]

そのプロパティにアクセスした時にロードされる（気がする）と思います。
->with('books')->get()にしたら最初から入る気がします

[n18marron]

Illuminate\Database\Eloquent\RelationNotFoundException
Call to undefined relationship [books] on model [App\Models\Lending].
でした。

[mikkame]

booksではなくbookですね・・・

[n18marron]

ありがとうございます！モデルを指定するんですね。勉強になりました。

[mikkame]

モデルではなく定義した名前ですね