查询整个类与类中的第一个对象 [英] Query entire class vs first object in the class

问题描述

在我的云代码中，我想检索消息"类中的第一个对象.然后我想从该对象中获取一些信息，将其发送到另一个类，最后从我最初从中提取的消息"类中删除该对象.

In my cloud code I want to retrieve the first object in the "Messages" class. Then i want to grab some information from that object, send it to another class, and finally delete that object from the "Messages" class i originally pulled it from.

我的问题是我是否需要查询整个Messages"类才能获取其中的第一个对象?我不想因为代码效率低下而降低我的应用速度.

My question is do i need to query the entire "Messages" class just to get the first object in it? I don't want to slow down my app due to inefficient code.

Parse.Cloud.afterSave("sendMessage", function(Parse.Message, response) {
  var body = null;
  var senderName = null;
  var senderId = null;
  var randUsers = [];

  var query = new.Parse.Query(Parse.Message);
  query.find({
    success: function(results){
      body.push(results[1].get("messageBody"));
      senderName.push(results[1].get("senderName"));
      senderId.push(results[1].get("senderId"));
      response.success(getUsers);
    }, 
    error: funtion(error){
      response.error("Error");
    }

  });
});

为避免混淆:getUsers"是任意函数调用.

to avoid confusion: "getUsers" is an arbitrary function call.

推荐答案

要从类中检索条目，您需要查询表.但是，您的问题是获取不需要获取所有记录的第一条记录.从您的代码中，我可以看到您获得了结果数组的第一条记录 (result[1]).您可以应用该解决方案；获取要查询的类的第一条记录.您可以通过两种方式做到这一点；您可以为查询设置限制 1，也可以使用 first() 方法.Parse.Query JS API 链接如下；

To retrieve entry from class, you need the query the table. However, your problem is getting the first record which does not require getting the all record. From your code I can see that you get the first record of result array (result[1] ). You can apply the solution; getting the first record of the class that you want to query. You can do it via two ways; either you can set the limit 1 to your query or you can use the first() method. The Parse.Query JS API link is below;

https://parse.com/docs/js/symbols/Parse.查询.html

检查限制和第一种方法.希望这可以帮助.问候.

Check the limit and first methods. Hope this helps. Regards.

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