猫鼬的findOne方法检索缺少_id的有效文档

本文介绍了猫鼬的findOne方法检索缺少_id的有效文档的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

我目前遇到一个非常奇怪的猫鼬错误，我不知道是什么导致了这个问题.当我调用findOne方法时，我得到一个有效的实例，只有_id字段未初始化.当我尝试将更改保存在该文档中时，它会因

I'm currently on a very weird mongoose error and I don't know what is causing this problem. When I call findOne method, I get a valid instance, with only the _id field not initialized. When I'm trying to save the changes in that document it crashes with

{ [CastError: Cast to ObjectId failed for value "[object Object]" at path "_id"]
 message: 'Cast to ObjectId failed for value "[object Object]" at path "_id"',
 name: 'CastError',
 type: 'ObjectId',
 value:
   { from_node_id: 52e10f6acce9daa7f3bf3162,
     target_id: 'a' },
 path: '_id' }

我有一个简单的架构定义:

I have a simple Schema Definition:

var mongoose = require('mongoose'),
Schema = mongoose.Schema;

var transitionProbabilitySchema;
transitionProbabilitySchema = new Schema({
   _id: {
       from_node_id: {type: Schema.Types.ObjectId, ref: "Zone"}
   },
   value: {
       total_transition_count: Number,
       probabilities: [
           {to_node_id: {type: Schema.Types.ObjectId, ref: "Zone"}},
           {probability: Number}
       ]}
}, {collection: 'transitionProbability'});

module.exports = mongoose.model('transitionProbability', transitionProbabilitySchema);

现在我打电话给

TransitionProbability.findOne({"_id.from_node_id": from_node_id},
        function (err, tp) {
            if (err) {
                handleError('error - tp not found', err, callback);
            } else {
                 // some modification of tp and then save
            }
        }

猫鼬返回文档，但只有_id未初始化.当我尝试保存更改后的文档时，而不是之前，整个功能崩溃.我还将该文档记录到控制台以验证它只是缺少"_id"字段.

Mongoose returns the document, but only _idis not initialized. The whole function crashes when I am trying to save the altered document and not before. I also logged the document to the console to verify it is just the `_id' field missing.

PS:请注意，from_node_id是从另一个查询中提取的，并且是有效的ObjectId.

PS: note, that the from_node_id is extracted from another query and is a valid ObjectId.

有什么想法吗?预先感谢您的帮助！

Any ideas? Thanks in advance for your help!

手动设置_id字段似乎也不起作用.甚至更有趣:尝试其他方法时，我意识到例如findOneAndUpdate确实冻结了整个node.js应用程序，没有任何日志.只是不会继续.

setting the _id field manually does not seem to work either. Even more interesting: while trying out other methods, I recognized that findOneAndUpdatefor example does freeze the whole node.js app, without any log. It just doesn't continue.

whole

猫鼬的findOne方法检索缺少_id的有效文档

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