Question

摘要

尝试调用关系时收到以下错误：

类Illuminate \ Database \ Eloquent \ Relations \ BelongsToMany的对象无法转换为字符串

我的设置非常基础，由两个模型User和Role组成。

用户模型[User.php]

<?php
use Illuminate\Auth\UserInterface;

class User extends Eloquent implements UserInterface {

    protected $table = 'users';
    protected $hidden = array('password');
    protected $fillable = array('id', 'username', 'password');


    public function getAuthIdentifier() {
        return $this->getKey();
    }

    public function getAuthPassword() {
        return $this->password;
    }
}

角色模型[Role.php]

<?php
class Role extends Eloquent {

    protected $table = "roles";
    protected $fillable = array(
        'id',           
        'code',
        'name'
    );

    public function foo() {
        return $this->belongsToMany('User', 'map_role_user', 'role_id', 'user_id');
    }
}

最后我在routes文件中调用方法foo，例如：

Route::get('role', function() {
        return Role::find(1)->foo();  
    });

Answer 1

来自

https://laravel.com/docs/5.3/eloquent-relationships或https://laravel.com/docs/4.2/eloquent#relationships

如果将集合强制转换为字符串，它将以JSON：

的形式返回

<?php
$roles = (string) User::find(1)->roles;

Answer 2

如果您不想为查询添加更多约束，则必须使用dynamic properties概念。所以，

$user = App\User::find(1);

foreach ($user->posts as $post) {
    //
}

如果您想添加更多约束，请执行此操作

App\User::find(1)->posts()->where('title', 'LIKE', '%Best%')->get()

Laravel ORM关系方法'BelongsToMany'抛出错误

2 个答案: