保存多对多关系，不存在同步/附加吗? [英] Saving many-to-many relationship, sync/attach doesn't exist?

问题描述

我在多对多关系中有以下两个2个模型:

I have two following 2 models in many-to-many relationship :

use Illuminate\Database\Eloquent\Model;

class Permission extends Model
{
    /**
     * The database table used by the model.
     *
     * @var string
     */
    protected $table = 'permissions';

    /*
    |--------------------------------------------------------------------------
    | Relationship Methods
    |--------------------------------------------------------------------------
    */

    /**
     * many-to-many relationship method
     *
     * @return QueryBuilder
     */
    public function roles()
    {
        return $this->belongsToMany('App\Admin\Role');
    }

}

和

class Role extends Model
{
    /**
     * The database table used by the model.
     *
     * @var string
     */
    protected $table = 'roles';

    /*
    |--------------------------------------------------------------------------
    | Relationship Methods
    |--------------------------------------------------------------------------
    */

    /**
     * many-to-many relationship method.
     *
     * @return QueryBuilder
     */
    public function users()
    {
        return $this->belongsToMany('App\Admin\User');
    }

    /**
     * many-to-many relationship method.
     *
     * @return QueryBuilder
     */
    public function permissions()
    {
        return $this->belongsToMany('App\Admin\Permission');
    }
}

我在这里要做的是创建一个页面，可以在其中创建新角色，并将该角色与已创建的权限相关联:

What I'm trying to do here, is to create a page where new Role can be created, and associate that role with already created Permissions:

@foreach ($permissions as $permission)
                            <label class="checkbox">
                                <input type="checkbox" value="{{ $permission->id }}" name="permissions[]" id="permission_{{ $permission }} }}">
                                {{ $permission->permission_title }}
                            </label>
                        @endforeach

，并且在控制器中，我尝试了此操作以从页面中提取所选权限并保存所有内容:

and in the controller I tried this to extract selected permissions from the page and save everything:

// logic to save role
$role->save();
$permissions = Input::get('permissions');
$role->permissions->sync($permissions);

但是，执行完最后一条语句后，出现以下错误: exception 'BadMethodCallException' with message 'Method sync does not exist.' 我也为attach遇到了相同的错误.另外，我不确定是否应该在中间表permission_role的位置提供名称?谢谢.

However after the last statement is executed I get the following error: exception 'BadMethodCallException' with message 'Method sync does not exist.' The same error I get for attach as well. Also, I'm not sure if I'm supposed to provide somewhere the name of the intermediate table permission_role ? Thanks.

推荐答案

您需要使用以下内容:

$role->permissions()->sync($permissions);

别忘了()

更多说明:

$role->permissions是Collection实例.

$role->permissions is a Collection instance.

$role->permissions()是包含sync()方法

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