Question

我试图弄清楚控制器中的if if是否正确。它可以工作，不会产生错误，但是更新不起作用。即使它存在，它仍然会添加一个新的

public function store(Request $request)
{

    $collection = Collection::create([
        'assignment_id' => $request->input('assignment_id'),
        'bag_id' => $request->input('bag_id'),
        'weight' => $request->input('weight')
    ]);


    $station = Collection::join('assignments', 'collections.assignment_id', '=', 'assignments.id')
        ->join('stations', 'assignments.station_id', '=', 'stations.id')
        ->select('stations.id')
        ->where('collections.id', '=', $collection->id)
        ->first();

    $weight = Collection::join('assignments', 'collections.assignment_id', '=', 'assignments.id')
        ->join('stations', 'assignments.station_id', '=', 'stations.id')
        ->select('collections.weight')
        ->where('collections.id', '=', $collection->id)
        ->first();

    //query in selectings process that exists within a month
    $processexist = Process::select('*')
        ->where('bag_id', $request->input('bag_id'))
        ->whereMonth('created_at', date('m'))
        ->first();

    if($processexist == null)//if doesn't exist: create
    {
        $processes = Process::create([
            'bag_id' => $request->input('bag_id'),
            'station_id' => $station->id,
            'total_weight' => $weight->weight
        ]); 
    }
    else //if exist: update
    {
        $processes = Process::where('id', $processexist->id)
            ->update(['weight'=>sum($weight->weight)]);
    }

    return redirect('/collections');
}

在我的CollectionsController商店中，每次添加集合时，都会添加一个过程。如果该过程存在，则只会更新权重，而不会，它将添加新的权重。就像我说的那样，如果存在，它不会更新，但是会更新。希望您能帮我弄清楚。谢谢！

Answer 1

如果想求和，就不能尝试

 $processes = Process::where('id', $processexist->id)->first();
 $processes->weight += $weight->weight;
 $processes->save();

Answer 2

如果存在将返回它，否则创建一个（已经保存在数据库中）

$process = Process::findOrCreate(array $attributes, array $values = []);

如果存在将返回它，否则将实例化一个新的（不会保存在数据库中）；

$process = Process::findOrNew(array $attributes, array $values = []);

还有

Process::updateOrCreate(array $attributes, array $values = [])

https://laravel.com/api/5.5/Illuminate/Database/Eloquent/Builder.html#method_findOrNew

如果存在：更新，否则：在Laravel 5.5中插入

2 个答案: