php Laravel 在创建 Eloquent 对象时从空值创建默认对象
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Laravel Creating default object from empty value when creating an Eloquent object
提问by Chris
I'm trying to save an object to the database for a game I'm building on a website, but I keep getting this error:
我正在尝试将一个对象保存到我在网站上构建的游戏的数据库中，但我不断收到此错误：
Creating default object from empty value
Here's the code I'm using:
这是我正在使用的代码：
foreach( $input['items'] as $key=>$itemText ){
$item = ($input['itemIDs'][$key] === 'NA') ? new GameItem() : GameItem::find($input['itemIDs'][$key]);
// if updating this item, check that it is assigned to this game
if( !is_null($item->game_id) && $item->game_id != $game->id ){ continue; }
$item->game_id = $game->id;
$item->item = $itemText;
$item->answer = $input['answers'][$key];
$item->save();
}
The error occurs at the if statement. I tried commenting it out, and then the error occurred at the $item->game_id = $game->id; line.
错误发生在 if 语句中。我试着把它注释掉，然后错误发生在 $item->game_id = $game->id; 线。
I've var_dumped both $item and $game, and both are valid Eloquent objects. I even var_dumped the result of the if statement with no problems, so I'm at a loss as to what's happening.
我已经对 $item 和 $game 进行了 var_dump，它们都是有效的 Eloquent 对象。我什至 var_dumped if 语句的结果没有任何问题，所以我对发生的事情感到茫然。
I just noticed if I do
我只是注意到如果我这样做
var_dump($item->toArray()); die();
right before the $item->save(); line, it doesn't throw any errors and shows me the array just fine.
就在 $item->save() 之前；行，它不会抛出任何错误并向我显示数组就好了。
What could be the problem then? I suppose it has to do with saving the item, but I don't understand it at all.
那可能是什么问题呢？我想这与保存项目有关，但我根本不明白。
采纳答案by The Alpha
The following line:
以下行：
$item = ($input['itemIDs'][$key] === 'NA') ? new GameItem() : GameItem::find($input['itemIDs'][$key]);
Always doesn't return a GameItemobject so when you try to use a propertyon NULLvalue then this error appears. So you should always check if the $itemis not NULLusing something like this:
始终不返回GameItem对象，因此当您尝试使用propertyonNULL值时，会出现此错误。所以你应该总是检查是否$item没有NULL使用这样的东西：
if( !is_null($item) && $item->game_id != $game->id ) { continue; }
Instead of this (At first make sure $itemis not NULLbefore you use $item->game_id):
而不是这个（首先确保$item不是NULL在你使用之前$item->game_id）：
if( !is_null($item->game_id) && $item->game_id != $game->id ){ continue; }
