将对象 ID 推送到嵌套数组 MongoDB/Mongoose

Question

所以我正在尝试为我正在开发的应用程序做一个简单的 Thumbs Up 系统，但我在将用户 ID 推送到 likes 数组时遇到问题。这是我的代码的样子：

房间架构

const mongoose = require('mongoose');
const Schema = mongoose.Schema;

const classroomSchema = Schema({
    clName: String,
    clPosts: [{
        title: String,
        mssg: String,
        date: String,
        imageurl: String,
HERE==> likes: [{type: Schema.Types.ObjectId, ref: 'User'}] 
    }]
})

const Classroom = mongoose.model('Classroom', classroomSchema)
module.exports = Classroom

路由器

router.put('/put/classroom/post/like/:id', (req, res, next) => {
    var data = data = req.body
    Classroom.findByIdAndUpdate(
        {
            _id: req.params.id,
            "clPosts": { _id: data.post }
        },
        { $push: { "clPosts.$[outer].likes": [data.user] } },
        { "arrayFilters": [{ "outer._id": data.post }] }
    ).then((room) => {
         console.log("Done"); 
         res.json(room);
    }).catch(next)
})

我已经尝试在 SO 上遵循其他建议，但我不确定我的某些配置是否不正确，或者是否有更好的方法将对象推送到嵌套数组中。

基本设置是，有一个包含教室对象的教室集合。在教室里，有posts 对象数组，在里面，有一个likes 数组。这个想法是每当有人喜欢该帖子时，它将该用户的 ObjectID 保存到数组中，然后我用它来计算有多少喜欢，等等......

如果需要更多详细信息，请告诉我，MongoDB 没有关于嵌套数组的良好文档。

Answer 1

clPosts 是一个子文档。您通过_id -> "clPosts": { _id: data.post } 查询帖子，但我相信，查询应该是这样的："clPosts._id": { _id: data.post_id }

由于您使用mongoose，您可以这样做：

const mongoose = require('mongoose');
const Schema = mongoose.Schema;

const ClassRoomPostsSchema = new Schema({
    title: String,
    mssg: String,
    date: String,
    mageurl: String,
    likes: [] // you will push ids here or else, if you need to store more data, e.g. date/time when like was given, create a schema for Likes e.g. likes: [likeSchema.schema]
})

const ClassRoomSchema = new Schema({
    clName: String,
    clPosts: [ClassRoomPostsSchema.schema]
})

然后在你的代码中：

router.put('/put/classroom/post/like/:id', (req, res, next) => {
  ClassRoom.findOne({_id: req.params.id}, function(err, room) {
    if (err) return next(err);

    if (!room) return res.status(404).send('Classroom not found');

    //Find a post by id
    let post = ClassRoom.clPosts.id(data.post); // -> data.post_id

    if (!post) return res.status(404).send('Post not found');

    // Here you can push ids, but what is the idea behind? Maybe it makes more sense to count likes or push Like schemas (subdocument) to the array, e.g. post.likes.push(new Like(data));        
    post.likes.push();

    room.save(function(err) {
      if (err) return serverValidationError(req, res, err);
      res.status(200).send('success');
    });
  });      
})

Answer 2

试试这个方法

Classroom.findByIdAndUpdate(
        {
            _id: req.params.id,
            "clPosts._id": data.post
        },
        { $push: { "clPosts.$.likes": [data.user] } }
    ).then((room) => {
         console.log("Done"); 
         res.json(room);
    }).catch(next)