我有三个表（实例，用户，user_instance）。每个用户都可以分配给一个实例。一个实例可以有许多不同的用户。
我尝试通过使用Laravel 5.1 Eloquent和belongsTo（）函数，通过调用$ this-＆gt; user-＆gt; instance-＆gt; instance_id来获取特定用户所分配实例的instance_id。
无论我尝试过什么，我总是在我的AuthController.php中得到一个NULL结果：
数据库架构：
mysql> show columns from instances;
+------------+------------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+------------+------------------+------+-----+---------+----------------+
| id | int(10) unsigned | NO | PRI | NULL | auto_increment |
| name | varchar(150) | NO | | NULL | |
| key | varchar(150) | NO | | NULL | |
| created_at | int(11) | NO | | NULL | |
| updated_at | int(11) | NO | | NULL | |
+------------+------------------+------+-----+---------+----------------+
mysql> show columns from users;
+----------------+---------------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+----------------+---------------------+------+-----+---------+----------------+
| id | int(10) unsigned | NO | PRI | NULL | auto_increment |
| first_name | varchar(50) | YES | | NULL | |
| last_name | varchar(50) | YES | | NULL | |
| email | varchar(100) | NO | | NULL | |
| password | varchar(255) | NO | | NULL | |
| salt | varchar(255) | YES | | NULL | |
| remember_token | varchar(255) | YES | | NULL | |
| created_at | int(10) unsigned | NO | | NULL | |
| updated_at | int(10) | NO | | NULL | |
| last_login | int(10) unsigned | YES | | NULL | |
| ip_address | varchar(15) | NO | | NULL | |
| timezone | int(10) | YES | | NULL | |
| active | tinyint(1) unsigned | YES | | NULL | |
+----------------+---------------------+------+-----+---------+----------------+
mysql> show columns from user_instance;
+-------------+------------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+-------------+------------------+------+-----+---------+----------------+
| id | int(10) unsigned | YES | PRI | NULL | auto_increment |
| user_id | int(10) unsigned | NO | | NULL | |
| instance_id | int(10) unsigned | NO | | NULL | |
| created_at | int(11) | NO | | NULL | |
| updated_at | int(11) | NO | | NULL | |
+-------------+------------------+------+-----+---------+----------------+
应用/控制器/ AuthController.php
<?php
use App\Models\User;
use App\Models\Instance;
use App\Models\User_Instance;
class AuthController extends Controller {
...
die($this->user->instance); // Returns: NULL
...
}
?>
应用/型号/ Instance.php
<?php namespace App\Models;
use Illuminate\Database\Eloquent\Model;
class Instance extends Model
{
/**
* Indicates if the model should be timestamped.
*
* @var bool
*/
public $timestamps = true;
/**
* The database table used by the model.
*
* @var string
*/
protected $table = 'instances';
/**
* The tables primary key.
*
* @var string
*/
protected $primaryKey = 'id';
/**
* The attributes that are mass assignable.
*
* @var array
*/
protected $fillable = ['name', 'key', 'created_at', 'updated_at'];
/**
* The attributes excluded from the model's JSON form.
*
* @var array
*/
protected $hidden = [];
}
?>
应用/型号/ User_Instance.php
<?php namespace App\Models;
use Illuminate\Database\Eloquent\Model;
class User_Instance extends Model
{
/**
* Indicates if the model should be timestamped.
*
* @var bool
*/
public $timestamps = true;
/**
* The database table used by the model.
*
* @var string
*/
protected $table = 'user_instance';
/**
* The tables primary key.
*
* @var string
*/
protected $primaryKey = 'id';
/**
* The attributes that are mass assignable.
*
* @var array
*/
protected $fillable = ['user_id', 'instance_id', 'created_at', 'updated_at'];
/**
* The attributes excluded from the model's JSON form.
*
* @var array
*/
protected $hidden = [];
}
?>
应用/型号/ user.php的
<?php namespace App\Models;
use Illuminate\Auth\Authenticatable;
use Illuminate\Database\Eloquent\Model;
use Illuminate\Auth\Passwords\CanResetPassword;
use Illuminate\Contracts\Auth\Authenticatable as AuthenticatableContract;
use Illuminate\Contracts\Auth\CanResetPassword as CanResetPasswordContract;
use Zizaco\Entrust\Traits\EntrustUserTrait;
class User extends Model implements AuthenticatableContract, CanResetPasswordContract
{
use Authenticatable, CanResetPassword, EntrustUserTrait;
/**
* Indicates if the model should be timestamped.
*
* @var bool
*/
public $timestamps = true;
/**
* The database table used by the model.
*
* @var string
*/
protected $table = 'users';
/**
* The tables primary key.
*
* @var string
*/
protected $primaryKey = 'id';
/**
* The attributes that are mass assignable.
*
* @var array
*/
protected $fillable = [
'first_name',
'last_name',
'email',
'password',
'salt',
'remember_token',
'created_at',
'updated_at',
'last_login',
'ip_address',
'timezone',
'active'
];
/**
* The attributes excluded from the model's JSON form.
*
* @var array
*/
protected $hidden = ['password', 'remember_token'];
/**
* Map the instance with the user.
*
* @var int
*/
public function instance()
{
return $this->belongsTo('App\Models\User_Instance');
}
}
?>
答案 0 :(得分：1)
public function instance()
{
return $this->belongsTo('App\Models\User_Instance');
}
belongsTo，在上面的方法中，使用snakecase特别应用where条件（即instance_id）..但在你的情况下会导致错误的结果或根本没有结果（你想在user_id上映射）
正如Laravel - Eloquent所说。 如果父模型上的外键不是snakecase名称（instance_id），则可以将自定义键名作为第二个参数传递给belongsTo方法：
return $this->belongsTo('App\Models\User_Instance','user_id');