《PHP編程：Laravel 5框架學習之Eloquent 關系》要點：
本文介紹了PHP編程：Laravel 5框架學習之Eloquent 關系，希望對您有用。如果有疑問，可以聯系我們。
一個用戶可能有多個文章,一個文章是某個用戶書寫的,這就是關系.同樣文章中可能包括多個 TAG,而一個 TAG 可能關聯多個文章.PHP實戰
在項目中,我們已經有了 User.php,也就是用戶模型,查看一下,相當簡單.我們希望直接使用 $user->articles() 的形式獲取全部文章,讓我們修改 user 模型：PHP實戰
public function articles() {
return $this->hasMany('App\Article');
}
但是我們僅僅完成了關系中的一端,讓我們來處理另一端.我們希望的形式是 $article->user() ,讓我們修改 article 模型.PHP實戰
public function user() {
return $this->belongsTo('App\User');
}
在我們的數據庫中,文章模型沒有用戶的外鍵,我們需要設置,修改 create_article_table.phpPHP實戰
Schema::create('articles', function(Blueprint $table)
{
$table->increments('id');
//指定外鍵列
$table->integer('user_id')->unsigned();
$table->string('title');
$table->text('body');
$table->timestamp('published_at');
$table->timestamps();
//生成外鍵
$table->foreign('user_id')
->references('id')
->on('users')
->onDelete('cascade');
});
因為我們只是在開發階段,還沒有上線運行,我們可以直接修改數據庫遷移文件,回滾然后遷移即可,但是如果上線運行的話,應該新建一個遷移.PHP實戰
php artisan migrate:refresh #輸出信息 Rolled back: 2015_03_28_050138_create_article_table Rolled back: 2014_10_12_100000_create_password_resets_table Rolled back: 2014_10_12_000000_create_users_table Nothing to rollback. Migrated: 2014_10_12_000000_create_users_table Migrated: 2014_10_12_100000_create_password_resets_table Migrated: 2015_03_28_050138_create_article_table Migrated: 2015_03_28_051200_add_excerpt_to_articels_table
現在讓我們使用 tinker 來創建一個用戶.PHP實戰
php artisan tinker
Psy Shell v0.4.1 (PHP 5.4.16 ― cli) by Justin Hileman
#下面是執行過程
>>> $user = new App\User;
=> <App\User #000000007f1ad61a000000006497cc4f> {}
>>> $user->name = 'zhang jinglin';
=> "zhang jinglin"
>>> $user->email = 'zjl@example.com';
=> "zjl@example.com"
>>> $user->password = bcrypt('pass');
=> "$2y$10$Nbl2b9wqd.rXqKEsd3pRSOoIyFAFIhbqf71BufwDfS3Guv21SlEx2"
>>> $user->save();
=> true
>>> App\User::first()->toArray();
=> [
"id" => "1",
"name" => "zhang jinglin",
"email" => "zjl@example.com",
"created_at" => "2015-03-31 03:24:55",
"updated_at" => "2015-03-31 03:24:55"
]
>>>
現在我們需要新發布的文章和用戶關聯,我們暫時先修改 form_partial.blade.php 來暗藏一個用戶id,只是暫時：PHP實戰
同時要修改模型的 $fillabel 屬性,以便我們的 Mass Assisment.PHP實戰
protected $fillable = [
'title',
'body',
'published_at',
'user_id' //臨時設置
];
OK,添加一個文章.我們使用 tinker 來查看一下.PHP實戰
php artisan tinker
Psy Shell v0.4.1 (PHP 5.4.16 ― cli) by Justin Hileman
>>> App\Article::first()->toArray();
=> [
"id" => "1",
"user_id" => "1",
"title" => "User 1 Article",
"body" => "User 1 Body",
"published_at" => "2015-03-31 08:00:00",
"created_at" => "2015-03-31 04:17:58",
"updated_at" => "2015-03-31 04:17:58",
"excerpt" => null
]
#獲取用戶
>>> $user = App\User::first();
=> <App\User #0000000051cbb9d70000000073e11a3e> {
id: "1",
name: "zhang jinglin",
email: "zjl@example.com",
created_at: "2015-03-31 03:24:55",
updated_at: "2015-03-31 03:24:55"
}
#獲取用戶文章
>>> $user->articles()->toArray();
BadMethodCallException with message 'Call to undefined method Illuminate\Database\Query\Builder::toArray()'
>>> $user->articles->toArray();
=> [
[
"id" => "1",
"user_id" => "1",
"title" => "User 1 Article",
"body" => "User 1 Body",
"published_at" => "2015-03-31 08:00:00",
"created_at" => "2015-03-31 04:17:58",
"updated_at" => "2015-03-31 04:17:58",
"excerpt" => null
]
]
#為什么使用 $user->articles 而不是 #user->articles()?
#事實上,$user->articles()返回的是關系,如果你想用 articles() 你需要這樣用
>>> $user->articles()->get()->toArray();
=> [
[
"id" => "1",
"user_id" => "1",
"title" => "User 1 Article",
"body" => "User 1 Body",
"published_at" => "2015-03-31 08:00:00",
"created_at" => "2015-03-31 04:17:58",
"updated_at" => "2015-03-31 04:17:58",
"excerpt" => null
]
]
#你只能使用 articles() 來進行下一步的工作,好比下面的查詢
$user->articles()->where('title', 'User 1 Article')->get();
#我們也可以通過 article 獲取 user
>>> $article = App\Article::first();
=> <App\Article #0000000051cbb9d60000000073e11a3e> {
id: "1",
user_id: "1",
title: "User 1 Article",
body: "User 1 Body",
published_at: "2015-03-31 08:00:00",
created_at: "2015-03-31 04:17:58",
updated_at: "2015-03-31 04:17:58",
excerpt: null
}
>>> $article->user;
=> <App\User #0000000051cbb92d0000000073e11a3e> {
id: "1",
name: "zhang jinglin",
email: "zjl@example.com",
created_at: "2015-03-31 03:24:55",
updated_at: "2015-03-31 03:24:55"
}
>>>
以上所述就是本文的全部內容了,希望大家能夠喜歡.PHP實戰
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