One To Many relationship hasMany và phương thức thêm vô cùng hay (ok)

https://www.youtube.com/watch?v=rb2Tf8zByRU&t=545s

0:56 hasMany()
7:25 optional() helper function
8:42 Default Models in belongsTo() relation: withDefault(); 
11:08 Querying Relationship Existence: has(), whereHas()
12:55 Querying Relationship Absence: doesntHave(), whereDoesntHave()

Ví dụ 1:

C:\xampp\htdocs\hanam.com\app\User.php

<?php
namespace App;
use Illuminate\Foundation\Auth\User as Authenticatable;
use Illuminate\Notifications\Notifiable;
class User extends Authenticatable {
  use 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 function address() {
    return $this->hasOne(Address::class);
  }
  public function addresses() {
    return $this->hasMany(Address::class); 
  }
}

C:\xampp\htdocs\hanam.com\routes\web.php

<?php

use Illuminate\Support\Facades\Route;

/*
|--------------------------------------------------------------------------
| Web Routes
|--------------------------------------------------------------------------
|
| Here is where you can register web routes for your application. These
| routes are loaded by the RouteServiceProvider within a group which
| contains the "web" middleware group. Now create something great!
|
 */

Route::get('/', function () {
  return view('welcome');
});
Auth::routes();

Route::get('/home', 'HomeController@index')->name('home');
// Route::get('/user', function(){
//   factory(\App\User::class,5)->create();
// });
Route::get('/user', function () {
	// $user  = factory(\App\User::class)->create();
	// \App\Address::create([
	// 	"user_id" => $user->id,
	// 	"country" => "Ha Nam 10"
	// ]);
	// $user->address()->create([
	// 	"country" => "Ha Nam 9"
	// ]);
  // $users = \App\User::all();
  // $addresses = \App\Address::all();
  $users = \App\User::with('addresses')->get();
  return view('users.index', compact('users'));
});

C:\xampp\htdocs\hanam.com\resources\views\users\index.blade.php

@extends('layouts.app')
@section('content')
<div class="row justify-content-center">
	<div class="col-md-8">
		<div class="card">
			{{-- @foreach ($users as $user)
				<h2>{{$user->name}}</h2>
				<p>{{$user->address->country}}</p>
			@endforeach --}}
			{{-- @foreach ($addresses as $address)
				<h2>{{$address->country}}</h2>
				<p>{{$address->user->name}}</p>
			@endforeach --}}
			@foreach ($users as $user)
				<h2>{{$user->name}}</h2>
				@foreach ($user->addresses as $address)
					<p>{{$address->country}}</p>
				@endforeach
			@endforeach
		</div>
	</div>
</div>
@endsection

C:\xampp\htdocs\hanam.com\app\Address.php

$users[0]->addresses()->create

<?php
namespace App;
use Illuminate\Database\Eloquent\Model;
class Address extends Model {
  protected $fillable = [
    'user_id', 'country',
  ];
  public function user() {
  	return $this->belongsTo(User::class);
  }
}

Ví dụ 2:

C:\xampp\htdocs\hanam.com\routes\web.php

<?php

use Illuminate\Support\Facades\Route;

/*
|--------------------------------------------------------------------------
| Web Routes
|--------------------------------------------------------------------------
|
| Here is where you can register web routes for your application. These
| routes are loaded by the RouteServiceProvider within a group which
| contains the "web" middleware group. Now create something great!
|
 */

Route::get('/', function () {
  return view('welcome');
});
Auth::routes();

Route::get('/home', 'HomeController@index')->name('home');
// Route::get('/user', function(){
//   factory(\App\User::class,5)->create();
// });
Route::get('/user', function () {
	// $user  = factory(\App\User::class)->create();
	// \App\Address::create([
	// 	"user_id" => $user->id,
	// 	"country" => "Ha Nam 10"
	// ]);
	// $user->address()->create([
	// 	"country" => "Ha Nam 9"
	// ]);
  // $users = \App\User::all();
  // $addresses = \App\Address::all();
  $users = \App\User::with('addresses')->get();
  $users[0]->addresses()->create([
  	"country" => "Ha Nam 4"
  ]);
  return view('users.index', compact('users'));
});

Ví dụ 3: Kiểm tra nếu >= 2 posts thì in ra :)

<?php

use Illuminate\Support\Facades\Route;

/*
|--------------------------------------------------------------------------
| Web Routes
|--------------------------------------------------------------------------
|
| Here is where you can register web routes for your application. These
| routes are loaded by the RouteServiceProvider within a group which
| contains the "web" middleware group. Now create something great!
|
 */

Route::get('/', function () {
  return view('welcome');
});
Auth::routes();

Route::get('/home', 'HomeController@index')->name('home');
// Route::get('/user', function(){
//   factory(\App\User::class,5)->create();
// });
Route::get('/user', function () {
	// $user  = factory(\App\User::class)->create();
	// \App\Address::create([
	// 	"user_id" => $user->id,
	// 	"country" => "Ha Nam 10"
	// ]);
	// $user->address()->create([
	// 	"country" => "Ha Nam 9"
	// ]);
  // $users = \App\User::all();
  // $addresses = \App\Address::all();
  // $users = \App\User::with('addresses')->get();
  // $users = \App\User::get();
  // Hoặc dùng cách khác 
  // $users = \App\User::with('posts')->get();
  $users = \App\User::has('posts','>=',2)->with('posts')->get();
  // $users[0]->posts()->create([
  // 	"title" => "Post 1 Test"
  // ]);
  // $users[2]->posts()->create([
  // 	"title" => "Post 2 Test"
  // ]);
  return view('users.index', compact('users'));
});
Route::get('/posts', function () {
	// \App\Post::create([
	// 	'user_id' => 1,
	// 	'title' => 'Post title 1'
	// ]);
	$posts = \App\Post::get();
	return view('posts.index',compact('posts'));
});

Ví dụ 4: Lọc trong tiêu đề có cụm từ "Post 2" thì lấy ra bài viết.

<?php

use Illuminate\Support\Facades\Route;

/*
|--------------------------------------------------------------------------
| Web Routes
|--------------------------------------------------------------------------
|
| Here is where you can register web routes for your application. These
| routes are loaded by the RouteServiceProvider within a group which
| contains the "web" middleware group. Now create something great!
|
 */

Route::get('/', function () {
  return view('welcome');
});
Auth::routes();

Route::get('/home', 'HomeController@index')->name('home');
// Route::get('/user', function(){
//   factory(\App\User::class,5)->create();
// });
Route::get('/user', function () {
	// $user  = factory(\App\User::class)->create();
	// \App\Address::create([
	// 	"user_id" => $user->id,
	// 	"country" => "Ha Nam 10"
	// ]);
	// $user->address()->create([
	// 	"country" => "Ha Nam 9"
	// ]);
  // $users = \App\User::all();
  // $addresses = \App\Address::all();
  // $users = \App\User::with('addresses')->get();
  // $users = \App\User::get();
  // Hoặc dùng cách khác 
  // $users = \App\User::with('posts')->get();
  // $users = \App\User::has('posts','>=',2)->with('posts')->get();
  $users = \App\User::whereHas('posts',function($query) {
  	$query->where('title','like','%Post 2%');
  })->with('posts')->get();
  // $users[0]->posts()->create([
  // 	"title" => "Post 1 Test"
  // ]);
  // $users[2]->posts()->create([
  // 	"title" => "Post 2 Test"
  // ]);
  return view('users.index', compact('users'));
});
Route::get('/posts', function () {
	// \App\Post::create([
	// 	'user_id' => 1,
	// 	'title' => 'Post title 1'
	// ]);
	$posts = \App\Post::get();
	return view('posts.index',compact('posts'));
});

Ví dụ 4:Kiểm tra xem tác giả nào chưa có bài viết

<?php

use Illuminate\Support\Facades\Route;

/*
|--------------------------------------------------------------------------
| Web Routes
|--------------------------------------------------------------------------
|
| Here is where you can register web routes for your application. These
| routes are loaded by the RouteServiceProvider within a group which
| contains the "web" middleware group. Now create something great!
|
 */

Route::get('/', function () {
  return view('welcome');
});
Auth::routes();

Route::get('/home', 'HomeController@index')->name('home');
// Route::get('/user', function(){
//   factory(\App\User::class,5)->create();
// });
Route::get('/user', function () {
	// $user  = factory(\App\User::class)->create();
	// \App\Address::create([
	// 	"user_id" => $user->id,
	// 	"country" => "Ha Nam 10"
	// ]);
	// $user->address()->create([
	// 	"country" => "Ha Nam 9"
	// ]);
  // $users = \App\User::all();
  // $addresses = \App\Address::all();
  // $users = \App\User::with('addresses')->get();
  // $users = \App\User::get();
  // Hoặc dùng cách khác 
  // $users = \App\User::with('posts')->get();
  // $users = \App\User::has('posts','>=',2)->with('posts')->get();
  // $users = \App\User::whereHas('posts',function($query) {
  // 	$query->where('title','like','%Post 2%');
  // })->with('posts')->get();
  $users = \App\User::doesntHave('posts')->with('posts')->get();
  // $users[0]->posts()->create([
  // 	"title" => "Post 1 Test"
  // ]);
  // $users[2]->posts()->create([
  // 	"title" => "Post 2 Test"
  // ]);
  return view('users.index', compact('users'));
});
Route::get('/posts', function () {
	// \App\Post::create([
	// 	'user_id' => 1,
	// 	'title' => 'Post title 1'
	// ]);
	$posts = \App\Post::get();
	return view('posts.index',compact('posts'));
});