创建后如何在猫鼬中填充子文档？

为了填充引用的子文档，您需要显式定义ID所引用的文档集合（如

created_by: { type: Schema.Types.ObjectId, ref:'User' }

假设已定义了此引用，并且在其他方​​面也对您的架构进行了很好的定义，那么您现在可以

populate

populate('comments.created_by')

概念证明代码：

// Schemavar mongoose = require('mongoose');var Schema = mongoose.Schema;var UserSchema = new Schema({  name: String});var CommentSchema = new Schema({  text: String,  created_by: { type: Schema.Types.ObjectId, ref: 'User' }});var ItemSchema = new Schema({   comments: [CommentSchema]});// Connect to DB and instantiate models    var db = mongoose.connect('enter your database here');var User = db.model('User', UserSchema);var Comment = db.model('Comment', CommentSchema);var Item = db.model('Item', ItemSchema);// Find and populateItem.find({}).populate('comments.created_by').exec(function(err, items) {    console.log(items[0].comments[0].created_by.name);});

最后请注意，该方法

populate

item.save(function(err, item) {    Item.findOne(item).populate('comments.created_by').exec(function (err, item) {        res.json({ status: 'success', message: "You have commented on this item", comment: item.comments.id(comment._id)        });    });});