laravel 容器注入的坑

今天遍历添加数据时遇到个坑，哪位大神知道什么原因？？

起初的代码是这样的：（部分）

public function addActive(Request $request, Activenorms $activenorms){
$specifications = $request->get('specification');     //活动规格

if(!$specifications || !is_array($specifications)){
   return response()->json(['message' => '请填写正确活动规格'], 500);
}

  foreach ($specifications as $key=>$value) {
     $activeNorms->active_id=$id;
     $activeNorms->active_price_name=$value['active_price_name'];
     $activeNorms->active_price_money=$value['active_price_money'];
     $activeNorms->active_max_players=$value['active_max_players'];
     $activeNorms->save();
  }

}

这样的代码是无论数组中有多少规格，永远只在数据表里添加了最后一条数据...

试着改成这样：

public function addActive(Request $request){
$specifications = $request->get('specification');     //活动规格

if(!$specifications || !is_array($specifications)){
   return response()->json(['message' => '请填写正确活动规格'], 500);
}

  foreach ($specifications as $key=>$value) {
     $activeNorms=new ActiveNorms();
     $activeNorms->active_id=$id;
     $activeNorms->active_price_name=$value['active_price_name'];
     $activeNorms->active_price_money=$value['active_price_money'];
     $activeNorms->active_max_players=$value['active_max_players'];
     $activeNorms->save();
  }

}

然后就能正常的添加多条数据了...

什么原因？？？有大神能解析下吗？？