laravel - 在Laravel 4中有很多通过数据透视表

我正在尝试与Eloquent建立hasManyTrough关系，但是尚不清楚它在文档中如何工作。

表格:

users
   - id
   - firstname
   - ...etc

accounts
   - id
   - user_id
   - username
   - ...etc

roles
   - id
   - permissions

account_role
   - id
   - account_id
   - role_id

模型

<?php
class User extends Eloquent {

    public function account()
    {
        return $this->hasOne('Account');
    }

    // This is what I'm trying to achieve
    public function roles()
    {
        return $this->hasManyThrough('Role', 'Account');
    }
}

class Role extends Eloquent {

    public function accounts()
    {
        return $this->belongsToMany('Account')->withTimestamps();
    }
}

class Account extends Eloquent {

    public function user()
    {
        return $this->belongsTo('User');
    }
}

错误和问题
我得到的错误是:SQLSTATE[42S22]: Column not found: 1054 Unknown column 'roles.account_id' in 'on clause'
我知道我可以做些$user->account->roles，但是我希望能够做$user->roles。如何正确设置？

最佳答案

最后，我能够通过执行以下操作解决此问题:

class User extends Eloquent {

    /**
     * @return \Illuminate\Database\Eloquent\Relations\BelongsToMany
     */
    public function roles()
    {
        return $this->account->belongsToMany('Navicula\Entities\Role');
    }
}

我怀疑这不会急于加载帐户，从而导致大量查询开销。但是，当我使用User::with('roles')->limit(100)->get();尝试并记录查询时，运行了以下查询:

SELECT * FROM `users` WHERE `users`.`deleted_at` IS NULL LIMIT 100
SELECT * FROM `accounts` WHERE `accounts`.`deleted_at` IS NULL LIMIT 1
SELECT `roles`.*, `account_role`.`account_id` as `pivot_account_id`, `account_role`.`role_id` as `pivot_role_id` FROM `roles` inner join `account_role` on `roles`.`id` = `account_role`.`role_id` WHERE `account_role`.`account_id` in ('1', '2', '3', '4', '5', '6', '7', '8', '9', '10', '11', '12', '13', '14', '15', '16', '17', '19', '20', '21', '22', '23', '24', '25', '26', '27', '28', '29', '30', '31', '32', '33', '34', '35', '36', '37', '38', '39', '40', '41', '42', '43', '44', '45', '46', '47', '48', '49', '50', '51', '52', '53', '54', '55', '56', '57', '58', '60', '61', '62', '63', '64', '65', '67', '68', '70', '71', '72', '73', '74', '75', '78', '79', '80', '81', '82', '83', '84', '85', '86', '87', '88', '89', '90', '91', '92', '93', '94', '95', '96', '97', '98', '99', '100', '101', '102', '103', '104', '105', '106')

这正是我们想要的。谢谢泰勒;-)

关于laravel - 在Laravel 4中有很多通过数据透视表，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/24261637/