Php 检查行是否存在，以及是否未插入数据

我有一个雄辩的模型，在我的一个表中创建新条目。我遇到的问题是，每次页面运行时，都会反复插入数据。如何检查该数据是否已存在于该表中，如果该数据不存在，则插入该特定数据

        foreach($xml as $product) {        

        //var_dump($product); die;

        Order::where('id', '=', $product->reference)->update(
            array(
                'invoice_id' => $product['orderid'],
                'shipped' => $product['shipped'],
                'processed' => $product['processed'],
                'problem' => $product['problem'],
            )
        );

        $tracking = new OrderTrack();
        $tracking->invoice_id = $product['orderid'];
        $tracking->shipper = $product->shipping->shipper;
        $tracking->shipping_method = $product->shipping->shipping_method;
        $tracking->shipping_date = $product->shipping->shipping_date;
        $tracking->shipping_cost = $product->shipping->shipping_cost;
        $tracking->tracking_number = $product->shipping->tracking_number;
        if(!empty($product->shipping->shipping_notes)) {
            $tracking->shipping_notes = $product->shipping->shipping_notes;
        }

        $tracking->save();
        echo'done';
    }

OrderTrack是我关心的代码部分。无论行是否已经存在，它都将创建一个新条目

$xml var_dump

利用firstOrNew

---

你能编辑你的代码以便我能在$xml之前看到它吗？这是一个转换后的xml文件，我把一些代码放在了问题中。希望有帮助！谢谢我对eloquent一点也不熟悉，只是php和mysql为什么不从表中选择查询，然后如果查询结果不是空的，就用xml插入数据？是的，我想过这样做，但必须有一种方法在eloquent中这样做。谢谢你的关注！看看这个，它可能对你有帮助

object(SimpleXMLElement)[294]
  public 'order' => 
    array (size=15)
      0 => 
        object(SimpleXMLElement)[295]
          public '@attributes' => 
            array (size=7)
              ...
          public 'reference' => string '3053' (length=4)
          public 'reference2' => 
            object(SimpleXMLElement)[310]
              ...
          public 'reference3' => 
            object(SimpleXMLElement)[311]
              ...
          public 'invoice' => 
            object(SimpleXMLElement)[312]
              ...
          public 'order_date' => string '2014-08-14 03:00:06' (length=19)
          public 'billing_date' => string '2014-08-14 00:00:00' (length=19)
          public 'changed' => string '2014-08-14 13:02:15' (length=19)
          public 'sender' => 
            object(SimpleXMLElement)[313]
              ...
          public 'receiver' => 
            object(SimpleXMLElement)[314]
              ...
          public 'shipping' => 
            object(SimpleXMLElement)[315]
              ...
          public 'products' => 
            object(SimpleXMLElement)[316]
              ...
      1 => 
        object(SimpleXMLElement)[296]
          public '@attributes' => 
            array (size=7)
              ...
          public 'reference' => string '3054' (length=4)
          public 'reference2' => 
            object(SimpleXMLElement)[328]
              ...
          public 'reference3' => 
            object(SimpleXMLElement)[329]
              ...
          public 'invoice' => 
            object(SimpleXMLElement)[330]
              ...
          public 'order_date' => string '2014-08-13 22:00:02' (length=19)
          public 'billing_date' => string '2014-08-14 00:00:00' (length=19)
          public 'changed' => string '2014-08-14 13:02:20' (length=19)
          public 'sender' => 
            object(SimpleXMLElement)[331]
              ...
          public 'receiver' => 
            object(SimpleXMLElement)[332]
              ...
          public 'shipping' => 
            object(SimpleXMLElement)[333]
              ...
          public 'products' => 
            object(SimpleXMLElement)[334]
              ...

        $tracking = OrderTrack::firstOrNew(array('invoice_id' => $product['orderid']));

        $tracking->invoice_id = $product['orderid'];

        $tracking->shipper = $product->shipping->shipper;

        $tracking->shipping_method = $product->shipping->shipping_method;

        $tracking->shipping_date = $product->shipping->shipping_date;

        $tracking->shipping_cost = $product->shipping->shipping_cost;

        $tracking->tracking_number = $product->shipping->tracking_number;

        if(!empty($product->shipping->shipping_notes)) {
            $tracking->shipping_notes = $product->shipping->shipping_notes;
        }

        $tracking->save();