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我对 laravel 中的以下错误感到震惊：有 2 个表用户和轨道具有多对多关系，中间表名称是 track_user 我正在尝试删除记录但无法删除 

Unhandled Exception

Message:

Call to a member function track() on a non-object
Location:

C:\wamp\www\integron\application\controllers\track.php on line 50

mysql错误：

SQL query:
DELETE FROM  `integron`.`tracks` WHERE  `tracks`.`id` =2

MySQL said: 

#1451 - Cannot delete or update a parent row: a foreign key constraint fails (`integron`.`track_user`, CONSTRAINT `track_user_project_id_foreign` FOREIGN KEY (`track_id`) REFERENCES `tracks` (`id`))

用户模型：

<?php 
class User extends Eloquent{
public static $table = 'users';
public function tracks()
    {
        return $this->has_many_and_belongs_to('Track');
    }

轨道型号：

<?php 
class Track extends Eloquent{
public static $table = 'tracks';
public function users()
    {
        return $this->has_many_and_belongs_to('User');
    }

控制器

//this funciton is working properly

public function post_trackUpdate($id){
    $track = Track::find($id);
    $track->name = Input::get('name');
    $track->description = Input::get('desc');
    $track->save();
}
//this funciton is not working properly
public function get_trackDelete($id){
    $track = Track::find($id);
    $track->delete();
}

..

//an alternate which i tried but didnt work either
public function get_trackDelete($id){
    $user=User::find($id);
    $user->tracks()->delete();
    Session::flash('result','track Details deleted');
    return Redirect::to('track');
}
4

2 回答 2

2

从 laravel 文档“附加的反面是分离：”

在http://four.laravel.com/docs/eloquent中寻找它

离开的例子：

$circle->users()->detach($user_id);
$circle->save();
于 2013-07-30T20:46:22.267 回答
1

您必须首先从复合 user_track 表中删除记录。只有这样，您才能删除跟踪表中的父记录。

于 2013-01-22T10:45:47.420 回答