無法刪除記錄中的一對多關係laravel雄辯

Question

我在laravel中遇到以下錯誤： 有2個表用戶和軌道與多對多的關係和中間表名稱是track_user我想刪除但無法記錄做

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錯誤：

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`)) 

用戶模型：

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

軌道型號：

<?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'); 
} 

Answer 1

從laravel文檔「重視的反面是分離：」在http://four.laravel.com/docs/eloquent

例

尋找它離開：

$circle->users()->detach($user_id); 
$circle->save(); 

Answer 2

你必須先刪除ŧ他從複合user_track表中記錄。只有這樣你才能刪除軌道表中的父記錄。