通过_id与猫鼬一起找到 [英] find by _id with Mongoose

问题描述

我遇到了一个带有猫鼬的简单findById的麻烦.

I am having trouble with a simple findById with mongoose.

确认该项目存在于数据库中

Confirmed the item exists in the DB

db.getCollection('stories').find({_id:'572f16439c0d3ffe0bc084a4'})

有猫鼬

  Story.findById(topic.storyId, function(err, res) {
    logger.info("res", res);
    assert.isNotNull(res);
  });

找不到它.

我还尝试了转换为mongoId，但仍然找不到(即使猫鼬据说可以为您完成此操作)

I also tried converting to a mongoId, still cannot be found (even though mongoose supposedly does this for you)

var mid = mongoose.Types.ObjectId(storyId);
let story = await Story.findOne({_id: mid}).exec();

我实际上正在尝试将其与打字稿一起使用，因此正在等待.

I'm actually trying to use this with typescript, hence the await.

我也尝试了Story.findById(id)方法，但仍然找不到.

I also tried the Story.findById(id) method, still cannot be found.

是否有一些陷阱只能通过简单的_id字段查找项目? _id是否必须在模式中? (文档说不)

Is there some gotcha to just finding items by a plain _id field? does the _id have to be in the Schema? (docs say no)

我可以通过Schema中的其他值找到，只是不能使用_id ...

I can find by other values in the Schema, just _id can't be used...

更新:为此我写了一个简短的测试.

update: I wrote a short test for this.

describe("StoryConvert", function() {


  it("should read a list of topics", async function test() {
    let topics = await Topic.find({});

    for (let i = 0; i < topics.length; i ++) {
      let topic = topics[i];
    // topics.forEach( async function(topic) {
      let storyId = topic.storyId;
      let mid = mongoose.Types.ObjectId(storyId);
      let story = await Story.findOne({_id: mid});
      // let story = await Story.findById(topic.storyId).exec();
      // assert.equal(topic.storyId, story._id);
      logger.info("storyId", storyId);
      logger.info("mid", mid);
      logger.info("story", story);
      Story.findOne({_id: storyId}, function(err, res) {
        if (err) {
          logger.error(err);
        } else {
          logger.info("no error");
        }
        logger.info("res1", res);
      });

      Story.findOne({_id: mid}, function(err, res) {
        logger.info("res2", res);
      });

      Story.findById(mid, function(err, res) {
        logger.info("res3", res);
        // assert.isNotNull(res);
      });

    }

  });


});

它将返回类似

Testing storyId 572f16439c0d3ffe0bc084a4

Testing mid 572f16439c0d3ffe0bc084a4

Testing story null

Testing no error

Testing res1 null

Testing res2 null

Testing res3 null

我注意到topic.storyId是一个字符串 不知道这是否会导致映射到其他表的任何问题. 我也尝试添加一些类型defs

I noticed that topic.storyId is a string not sure if that would cause any issues mapping to the other table. I tried also adding some type defs

  storyId: {
    type: mongoose.Schema.Types.ObjectId,
    required: false
  }

推荐答案

因为此查询在外壳中找到了文档，所以:

Because this query finds the doc in the shell:

db.getCollection('stories').find({_id:'572f16439c0d3ffe0bc084a4'})

这意味着文档中_id的类型实际上是字符串，而不是Mongoose期望的ObjectId.

That means that the type of _id in the document is actually a string, not an ObjectId like Mongoose is expecting.

要使用Mongoose查找该文档，您必须在Story的架构中将_id定义为:

To find that doc using Mongoose, you'd have to define _id in the schema for Story as:

_id: { type: String }

这篇关于通过_id与猫鼬一起找到的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！