node.js - Mongodb子文档填充

Question

您好，我有三个模型

帖子:

var PostSchema = new Schema({
title: {
    type: String,
    required: true,
    default: '',
},
content: {
    type: String,
    required: true,
    default: '',
},
community: {
    type: String,
    default: '',
},
price: {
    type: String,
    required: true,
    default: '',
},
location: {
    type: String,
    required: true,
    default: '',
},
images: {
    type:[],
    required: true,
},
user: {
    type: Schema.ObjectId,
    required: true,
    ref: 'User',
},
accepted : {
    type: [],
},
comments: {
    type: [Schema.Types.ObjectId],
    ref:"Comment"
}
});

用户:

var userSchema = mongoose.Schema({

local            : {
    email        : String,       
    password     : String,
},

firstName: { type: String, required: true },
lastName: { type: String, required: true },
location: { type: String, required: true },
profilepicture: { type: String },

});

评论

var CommentSchema = new Schema({
title: {
    type: String,
    default: '',
},
content: {
    type: String,
    default: '',
},
user: { 
    type: Schema.ObjectId, 
    ref: 'User' 
},
post: {
    type: Schema.ObjectId,
    ref: 'Post'
},
offer: {
    type: String,
    default: '',
}
});

我试图允许帖子模型拥有评论的对象 ID 数组，并让评论填充用户对象 ID。我在我的帖子路由中使用下面的代码，我可以填充所有评论，但无法填充评论的用户。理论上，这应该根据 mongo 文档工作，但事实并非如此。有什么想法吗？

app.get('/api/posts', function(req, res) {

Post.find().populate('user comments comments.user').exec(function(err, posts) {
    if (err) {
        res.render('error', {
            status: 500
        });
    } else {
        res.jsonp(posts);
    }
});
});

Answer 1

要执行您想要的操作，您需要在初始填充调用完成后对内部“评论”对象调用填充。在您的列表的简化版本中:

var async = require("async"),
    mongoose = require("mongoose"),
    Schema = mongoose.Schema;

mongoose.connect("mongodb://localhost/user");

var postSchema = new Schema({
  title: { type: String, required: true, default: '' },
  user: { type: Schema.Types.ObjectId, required: true, ref: 'User' },
  comments: [{ type: Schema.Types.ObjectId, ref: "Comment" }]
});

var userSchema = new Schema({
  name: String
});

var commentSchema = new Schema({
  content: String,
  user: { type: Schema.Types.ObjectId, ref: "User" },
  post: { type: Schema.Types.ObjectId, ref: "Post" }
});

var Post = mongoose.model( "Post", postSchema );
var User = mongoose.model( "User", userSchema );
var Comment = mongoose.model( "Comment", commentSchema );

在评论中填充“用户”将如下所示:

Post.find().populate("user comments").exec(function(err,docs) {

    async.forEach(docs,function(doc,callback) {
      Comment.populate( doc.comments,{ "path": "user" },function(err,output) {
        //console.log( "doc: " + doc );
        //console.log( "proc: " + output );
        callback();
      });

    },function(err) {
      console.log( "all: " + JSON.stringify(docs,undefined,4 ));
    });

});

或者您实际上正在处理您在帖子中找到的结果。重点是你的“评论”需要先填充，然后你可以调用.populate() ，使用模型形式，对结果中每个文档的整个“评论”数组进行分析。