猫鼬确定update-upsert正在执行插入或更新 [英] mongoose to determine update-upsert is doing insert or update

问题描述

我想测试用于更新的"upsert"选项是否正常.因此，我使用相同的键两次将对象"upsert"到mongodb中.但是它没有显示插入的消息.我错过了什么吗?

I want to test if "upsert" option for updating is woking fine. So I "upsert" an object into mongodb twice with same key. However it didn't show inserted message. Was I missing something ?

(mongodb:v2.6.3;猫鼬:3.8.15)

(mongodb : v2.6.3; mongoose : 3.8.15)

Member.findOneAndRemove({user_id : 1},
    function (err, doc) {
        if (!err) onsole.log(doc ? 'deleted' : 'not found');
}); // -> deleted, make sure user_id = 1 doesn't exist

Member.update({user_id : 1}, 
    {$set : {name:"name1"}}, 
    {upsert : true, new : false}, // new : false, so that I can detect original doc is null then know it's a new one.
    function (err, doc) {
    if (!err) {
        console.log(doc ? 'updated' : 'inserted')
    }
}); // -> updated ? But it shoule be inserted, right ?

Member.update({user_id : 1}, 
    {$set : {name:"name2"}}, 
    {upsert : true, new : false},
    function (err, doc) {
    if (!err) {
        console.log(doc ? 'updated' : 'inserted')
    }
}); // -> updated, yes, no problem.

谢谢您的提示.

============答案============

============ answer =============

使用 .findOneAndUpdate 代替.update！ 此外，请确保选项为{upsert:true， new:false }， 这样回调的第二个参数(doc)可以是原始文档，以防万一.

Use .findOneAndUpdate instead of .update ! Moreover, make sure option is {upsert: true, new : false}, so that the callback's 2nd parameter(doc) could be original document in case.

推荐答案

.update()猫鼬中的方法将三个参数传递给回调，分别为err，numAffected和raw响应.使用原始"对象查看发生了什么:

The .update() method in mongoose takes three arguments to the callback, being err, the numAffected, and a raw response. Use the "raw" object to see what happened:

Member.update({user_id : 1}, 
    {$set : {name:"name1"}}, 
    {upsert : true }, 
    function (err, numAffected, raw) {
    if (!err) {
        console.log(raw)
    }
});

您将看到这样的结构:

{ ok: true,
  n: 1,
  updatedExisting: false,
  upserted: [ { index: 0, _id: 5456fc7738209001a6b5e1be } ] }

因此，创建的任何新文档中总是存在n和'updatedExisting keys available, where the second is false on upserts and true otherwise. upserted will contain the _id`值.

So there is always the n and 'updatedExistingkeys available, where the second is false on upserts and true otherwise.upsertedwill contain the_id` values of any new documents created.

对于n或"numAffected"，基本上是1，在旧版写关注响应下匹配了文档.

As for n or the "numAffected", this is basically always 1 where a document was matched under the legacy write concern responses.

您可以使用Bulk Operations表单在MongoDB 2.6及更高版本中看到新的WriteResult响应:

You can see the new WriteResult response in MongoDB 2.6 and above using the Bulk Operations form:

var bulk = Member.collection.initializeOrderedBulkOp();
bulk.find({user_id : 1}.upsert().update({$set : {name:"name1"}});
bulk.execute(err,result) {
   console.log( JSON.stringify( result, undefined, 2 ) );
}

在第一次迭代中，您将得到如下内容:

Which on a first iteration you get something like this:

{
  "ok": 1,
  "writeErrors": [],
  "writeConcernErrors": [],
  "nInserted": 0,
  "nUpserted": 1,
  "nMatched": 0,
  "nModified": 0,
  "nRemoved": 0,
  "upserted": [
    {
      "index": 0,
      "_id": "5456fff138209001a6b5e1c0"
    }
  ]
}

第二秒钟具有相同的参数:

And a second with the same parameters like this:

{
  "ok": 1,
  "writeErrors": [],
  "writeConcernErrors": [],
  "nInserted": 0,
  "nUpserted": 0,
  "nMatched": 1,
  "nModified": 0,
  "nRemoved": 0,
  "upserted": []
}

该文档仅在实际更改的地方才标记为已修改".

And the document would only be marked as "modified" where something was actually changed.

因此，无论如何，.update()操作都不会返回修改后的文档或原始文档.这就是.findOneAndUpdate()方法，它是执行原子操作的基本.findAndModify()周围的猫鼬包装. .update()方法通常用于批量操作，因此不会返回文档内容.

So at any rate, .update() operations do not return the modified document or the original document. That is the .findOneAndUpdate() method, a mongoose wrapper around the basic .findAndModify() which performs an atomic operation. The .update() methods are typically meant for bulk operations and as such do not return document content.

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