无法删除一对多关系中的记录 laravel eloquent

Posted 2023-02-16

【中文标题】无法删除一对多关系中的记录 laravel eloquent

【英文标题】：unable to delete record in one to many relationship laravel eloquent

【发布时间】：2013-01-05 09:07:20

【问题描述】：

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');
    

跟踪模型：

<?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');

【参考方案1】：

来自 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();

【参考方案2】：

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。

【讨论】：

如何删除复合表中的记录？