Laravel，relationship，建立關聯

    //檔案：database/migrations/日期_編號_create_posts_table.php
    public function up()
    {
        Schema::create('posts', function (Blueprint $table) {
            $table->increments('id');
            $table->integer('user_id')->unsigned(); //正數
            $table->string('title');
            $table->text('content');
            $table->timestamps();
        });
    }

//下指令
php artisan migrate:refresh

資料庫的posts資料表將會增加user_id這個欄位

    //檔案：APP/user.php
    public function post(){
        return $this->hasOne('App\Post','user_id');
                                    //user_id其實是預設值
    }

//檔案：routes/web.php

use App\User;

Route::get('user/{id}/post', function($id) {
    return User::find($id)->post;
});

瀏覽器輸入：public/user/1/post

出現他那篇文章的文章物件

（post後面加->title，會出現標題，加->content，會出現內容）

hasOne與hasMany就是在建立關聯

參考文件：https://laravel.com/docs/5.5/eloquent-relationships#one-to-one

return $this->hasOne('App\Phone', 'foreign_key', 'local_key');
                                  //user表中的id //post表中代表user的id

//tinker
$post->first()->user()->get()
//就會跑出post與user的關聯（此篇文章的作者）

=> Illuminate\Database\Eloquent\Collection {#736
     all: [
       App\User {#714
         id: 1,
         name: "熊熊",
         email: "bear@gmail.com",
         created_at: null,
         updated_at: null,
       },
     ],
   }

 

---

 

//檔案：routes/web.php

use App\User;
use App\Post;

Route::get('post/{id}/user', function($id) {
    return Post::find($id)->user->name;
});

	//檔案：app/post.php
	public function user(){
		return $this->belongsTo('App\User');
	}

瀏覽器輸入：public/post/1/user

出現編號1的文章的作者

---

 

//檔案：routes/web.php

Route::get('/posts', function() {
    $user = User::find(1); //先確定有User這個model被use

    foreach ($user->posts as $post) {
    	echo $post->title . "<br>";
    }
});

   //檔案：APP/user.php
    public function posts(){
        return $this->hasMany('App\Post');
    }

瀏覽器輸入：public/posts

出現編號1會員的所有文章title

---

 

//下指令
php artisan make:model Role -m
//-m代表說會同時做migration

//下指令
php artisan make:migration create_users_roles_table --create=role_user
//新的名稱要放前面

    //檔案：database/migrations/日期_編號_create_roles_table.php
    public function up()
    {
        Schema::create('roles', function (Blueprint $table) {
            $table->increments('id');
            $table->string('name');
            $table->timestamps();
        });
    }

    //檔案：database/migrations/日期_編號_create_users_roles_table.php
    public function up()
    {
        Schema::create('role_user', function (Blueprint $table) {
            $table->increments('id');
            $table->integer('user_id');
            $table->integer('role_id');
            $table->timestamps();
        });
    }

//下指令
php artisan migrate

//SQL，增加一些資料
INSERT INTO `roles` (`id`, `name`, `created_at`, `updated_at`) 
VALUES (NULL, 'aministrator', NULL, NULL), (NULL, 'subscriber', NULL, NULL);

//SQL，讓使用者1是階級1（administor），使用者2是階級2（subscriber）
INSERT INTO `role_user` (`id`, `user_id`, `role_id`, `created_at`, `updated_at`) VALUES
(1, 1, 1, NULL, NULL),
(2, 2, 2, NULL, NULL);

    //檔案：APP/user.php
    public function roles(){
        return $this->belongsToMany('App\Role');
    }

//檔案：routes/web.php

Route::get('/user/{id}/role', function($id) {
    $user= User::find($id);
    foreach ($user->roles as $role) {
        return  $role->name;
    }
});

瀏覽器輸入：public/user/1/role

出現編號1會員的階級的名稱

---

 

//檔案：routes/web.php

Route::get('/user/{id}/role', function($id) {
    $user= User::find($id)->roles()->get();
            //選出這個user //找出他的階級
     return  $user;
});

瀏覽器輸入：public/user/1/role

[
	{
	    id: 1,
	    name: "aministrator",
	    created_at: null,
	    updated_at: null,
	    pivot:
	    {
	        user_id: 1,
	        role_id: 1
	    }
	}
]

---

    //檔案：APP/user.php
    public function roles(){
        // return $this->belongsToMany('App\Role','user_roles','user_id','role_id');
        //若表格命名為role_user，則可以使用預設值，不用上面那行
        return $this->belongsToMany('App\Role')->withPivot('created_at');
    }

//檔案：app/role.php

class Role extends Model
{
   public function users(){
   		return $this->belongsToMany('App\User');
   }
}

//檔案：routes/web.php

Route::get('user/pivot', function() {
    $user = User::find(1);
    foreach ($user->roles as $role) {
        return $role->pivot->created_at;
    }
});

瀏覽器輸入：public/user/peviot

出現編號1這個會員被賦予階級1時的時間