发布于 2015-10-01 08:06:45 | 327 次阅读 | 评论: 0 | 来源: 网友投递
Eloquent是Laravel的原始ActiveRecord是实现的，建立在Laravel的Fluent Query Builder之上的，所以Eloquent类和Fluent类是一样的，能实现复杂的SQL语句和非常直观表达出的表与表之间的关系一个用户可能有多个文章，一个文章是某个用户书写的，这就是关系。同样文章中可能包含多个 TAG，而一个 TAG 可能关联多个文章。
在项目中，我们已经有了 User.php，也就是用户模型，查看一下，相当简单。我们希望直接使用 $user->articles() 的形式获取全部文章，让我们修改 user 模型：
public function articles() {
return $this->hasMany('AppArticle');
}
但是我们仅仅完成了关系中的一端，让我们来处理另一端。我们希望的形式是 $article->user() ，让我们修改 article 模型。
public function user() {
return $this->belongsTo('AppUser');
}
在我们的数据库中，文章模型没有用户的外键，我们需要设置，修改 create_article_table.php
Schema::create('articles', function(Blueprint $table)
{
$table->increments('id');
//指定外键列
$table->integer('user_id')->unsigned();
$table->string('title');
$table->text('body');
$table->timestamp('published_at');
$table->timestamps();
//生成外键
$table->foreign('user_id')
->references('id')
->on('users')
->onDelete('cascade');
});
因为我们只是在开发阶段，还没有上线运行，我们可以直接修改数据库迁移文件，回滚然后迁移即可，但是如果上线运行的话，应该新建一个迁移。
php artisan migrate:refresh #输出信息 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
现在让我们使用 tinker 来创建一个用户。
php artisan tinker
Psy Shell v0.4.1 (PHP 5.4.16 — cli) by Justin Hileman
#下面是执行过程
>>> $user = new AppUser;
=> <AppUser #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
>>> AppUser::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"
]
>>>
现在我们需要新发布的文章和用户关联，我们暂时先修改 form_partial.blade.php 来隐藏一个用户id，只是暂时：
同时要修改模型的 $fillabel 属性，以便我们的 Mass Assisment。
protected $fillable = [
'title',
'body',
'published_at',
'user_id' //临时设置
];
OK，添加一个文章。我们使用 tinker 来查看一下。
php artisan tinker
Psy Shell v0.4.1 (PHP 5.4.16 — cli) by Justin Hileman
>>> AppArticle::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
]
#获取用户
>>> $user = AppUser::first();
=> <AppUser #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"
}
#获取用户文章
>>> $user->articles()->toArray();
BadMethodCallException with message 'Call to undefined method IlluminateDatabaseQueryBuilder::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
]
]
#为什么使用 $user->articles 而不是 #user->articles()?
#事实上，$user->articles()返回的是关系，如果你想用 articles() 你需要这样用
>>> $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() 来进行下一步的工作，比如下面的查询
$user->articles()->where('title', 'User 1 Article')->get();
#我们也可以通过 article 获取 user
>>> $article = AppArticle::first();
=> <AppArticle #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;
=> <AppUser #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"
}
>>>