使用可空foreighn鍵的完整性約束違規Laravel

Question

使用laravel和Eloquent進行數據庫訪問。我有一張桌子，上面有一個無形的鑰匙。 Whene我插入一個實體，沒有foreighnkey值，直接在數據庫中工作正常，但如果我喜歡插入一個元素使用laravel我得到以下錯誤。

SQLSTATE[23000]: Integrity constraint violation: 1452 Cannot add or 
update a child row: a foreign key constraint fails (`gpb-lvw`.`regale`, 
CONSTRAINT `regale_kunden_id_foreign` FOREIGN KEY (`kunden_id`) 
REFERENCES `kunden` (`id`)) (SQL: update `regale` set `bezeichnung` = 
xxxw, `updated_at` = 2015-07-20 10:28:17, `kunden_id` = where `id` = 4) 


in Connection.php line 631 
at Connection->runQueryCallback('update `regale` set `bezeichnung` = ?, `updated_at` = ?, `kunden_id` = ? where `id` = ?', array('xxxw', '2015-07-20 10:28:17', '', '4'), object(Closure)) in Connection.php line 591 
at Connection->run('update `regale` set `bezeichnung` = ?, `updated_at` = ?, `kunden_id` = ? where `id` = ?', array('xxxw', '2015-07-20 10:28:17', '', '4'), object(Closure)) in Connection.php line 406 
at Connection->affectingStatement('update `regale` set `bezeichnung` = ?, `updated_at` = ?, `kunden_id` = ? where `id` = ?', array('xxxw', '2015-07-20 10:28:17', '', '4')) in Connection.php line 349 
at Connection->update('update `regale` set `bezeichnung` = ?, `updated_at` = ?, `kunden_id` = ? where `id` = ?', array('xxxw', '2015-07-20 10:28:17', '', '4')) in Builder.php line 1741 
at Builder->update(array('bezeichnung' => 'xxxw', 'updated_at' => '2015-07-20 10:28:17', 'kunden_id' => '')) in Builder.php line 313 
at Builder->update(array('bezeichnung' => 'xxxw', 'updated_at' => '2015-07-20 10:28:17', 'kunden_id' => '')) in Model.php line 1520 
at Model->performUpdate(object(Builder), array()) in Model.php line 1454 
at Model->save() in Model.php line 1402 
at Model->update() in RegalController.php line 111 
at RegalController->update('4') 
at call_user_func_array(array(object(RegalController), 'update'), array('regale' => '4')) in Controller.php line 256 
at Controller->callAction('update', array('regale' => '4')) in ControllerDispatcher.php line 164 
at ControllerDispatcher->call(object(RegalController), object(Route), 'update') in ControllerDispatcher.php line 112 
at ControllerDispatcher->Illuminate\Routing\{closure}(object(Request)) 
at call_user_func(object(Closure), object(Request)) in Pipeline.php line 139 
at Pipeline->Illuminate\Pipeline\{closure}(object(Request)) 
at call_user_func(object(Closure), object(Request)) in Pipeline.php line 103 
at Pipeline->then(object(Closure)) in ControllerDispatcher.php line 114 
at ControllerDispatcher->callWithinStack(object(RegalController), object(Route), object(Request), 'update') in ControllerDispatcher.php line 69 
at ControllerDispatcher->dispatch(object(Route), object(Request), 'App\Http\Controllers\RegalController', 'update') in Route.php line 201 
at Route->runWithCustomDispatcher(object(Request)) in Route.php line 134 
at Route->run(object(Request)) in Router.php line 704 
at Router->Illuminate\Routing\{closure}(object(Request)) 
at call_user_func(object(Closure), object(Request)) in Pipeline.php line 139 
at Pipeline->Illuminate\Pipeline\{closure}(object(Request)) 
at call_user_func(object(Closure), object(Request)) in Pipeline.php line 103 
at Pipeline->then(object(Closure)) in Router.php line 706 
at Router->runRouteWithinStack(object(Route), object(Request)) in Router.php line 671 
at Router->dispatchToRoute(object(Request)) in Router.php line 631 
at Router->dispatch(object(Request)) in Kernel.php line 229 
at Kernel->Illuminate\Foundation\Http\{closure}(object(Request)) 
at call_user_func(object(Closure), object(Request)) in Pipeline.php line 139 
at Pipeline->Illuminate\Pipeline\{closure}(object(Request)) in ShareErrorsFromSession.php line 54 
at ShareErrorsFromSession->handle(object(Request), object(Closure)) 
at call_user_func_array(array(object(ShareErrorsFromSession), 'handle'), array(object(Request), object(Closure))) in Pipeline.php line 124 
at Pipeline->Illuminate\Pipeline\{closure}(object(Request)) in StartSession.php line 62 
at StartSession->handle(object(Request), object(Closure)) 
at call_user_func_array(array(object(StartSession), 'handle'), array(object(Request), object(Closure))) in Pipeline.php line 124 
at Pipeline->Illuminate\Pipeline\{closure}(object(Request)) in AddQueuedCookiesToResponse.php line 37 
at AddQueuedCookiesToResponse->handle(object(Request), object(Closure)) 
at call_user_func_array(array(object(AddQueuedCookiesToResponse), 'handle'), array(object(Request), object(Closure))) in Pipeline.php line 124 
at Pipeline->Illuminate\Pipeline\{closure}(object(Request)) in EncryptCookies.php line 59 
at EncryptCookies->handle(object(Request), object(Closure)) 
at call_user_func_array(array(object(EncryptCookies), 'handle'), array(object(Request), object(Closure))) in Pipeline.php line 124 
at Pipeline->Illuminate\Pipeline\{closure}(object(Request)) in CheckForMaintenanceMode.php line 42 
at CheckForMaintenanceMode->handle(object(Request), object(Closure)) 
at call_user_func_array(array(object(CheckForMaintenanceMode), 'handle'), array(object(Request), object(Closure))) in Pipeline.php line 124 
at Pipeline->Illuminate\Pipeline\{closure}(object(Request)) 
at call_user_func(object(Closure), object(Request)) in Pipeline.php line 103 
at Pipeline->then(object(Closure)) in Kernel.php line 118 
at Kernel->sendRequestThroughRouter(object(Request)) in Kernel.php line 86 
at Kernel->handle(object(Request)) in index.php line 54 
at require_once('C:\xampp\htdocs\gpb-lvw\public\index.php') in server.php line 21 

在控制器中的代碼如下所示：

$rules = array(
     'bezeichnung' => array('required','unique:regale') 
     ); 
    $validator = \Validator::make(\Input::all(),$rules); 

    if($validator->fails()){ 
    //$messages = $validator->messages(); 
    //return $messages; 
    return \Redirect::route('regale.create')->withErrors($validator)->withInput();  

    } 
    $bezeichnung = \Input::get('bezeichnung'); 
    $list=new Regal(); 
    $list->nummer= \Input::get('nummer'); 
    $list->maxPaletten= \Input::get('maxPaletten'); 
    $list->anzahlEbenen= \Input::get('anzahlEbenen'); 
    $list->kunden_id=\Input::get('kunden_id'); 
    $list->bezeichnung = $bezeichnung; 
    $list->save(); 
    \Session::flash('message',"Regal wurde angelegt."); 
    return \Redirect::route('regale.index'); 

，這是我的模型文件：

<?php namespace App\Models; 

use Illuminate\Database\Eloquent\Model; 

class Regal extends Model { 

    protected $table = "regale"; 
    public function listEinlagerung(){ 
    return $this->hasMany('App\Models\Einlagerung'); 
    } 
public function kunde(){ 
    return $this->belongsTo('App\Models\Kunde');   
} 
} 

Answer 1

看起來像你的問題可能是一個錯字。在你的控制器中你有kunden_id，在你的模型中你有kunde（no'n'）。檢查是否有效。

Answer 2

我明白了。問題是我將foreighn鍵設置爲空字符串。 $list->kunden_id=\Input::get('kunden_id');

因爲如果它未在Post中設置，它將返回一個空字符串。 因此，如果我將值設置爲null，它工作正常。

if(null===\Input::get('kunden_id') || trim(\Input::get('kunden_id'))==='') 
     { 
      $list->kunden_id=null; 
     } 
     else{ 
      $list->kunden_id=\Input::get('kunden_id'); 
     }