如何在我的数据库中填充多个路径？

Question

I want different values from the nested schema. How can I populate them so that every field is showing me its nested data and not the object ID? I'm using MongoDB and node/express.

This is my postDB where the post schema is defined:

 const mongoose = require('mongoose'); var postSchema = new mongoose.Schema({ title: { type:String, required:true }, body: { type:String, required:true }, comments:[{ type: mongoose.Schema.Types.ObjectId, ref: "comment" }], category:{ type:String, required:true }, creator: { type: mongoose.Schema.Types.ObjectId, ref: "user" } },{timestamps : true} ) module.exports = mongoose.model('postData', postSchema);

This is my commentDB which is referenced from the postDB:

 const mongoose = require('mongoose'); // Using the Schema constructor, create a new CommentSchema object // This is similar to a Sequelize model var CommentSchema = new mongoose.Schema({ // `body` is of type String creator: { type: mongoose.Schema.Types.ObjectId, ref: "user" }, body: String },{timestamps : true}); var Comment = mongoose.model("comment", CommentSchema); module.exports = Comment;

This is how I'm trying to populate:

 router.get('/READ', (req,res)=>{ posts.find({}, function (err, post) { if (err) { console.log(err); }else{ res.json({post}) } } ) .populate([{path:'creator'}, {path:'comments'}]) })

However the results i get from this does not populate every object ID.

For example:

 { "comments": [ { "_id": "5f8d91d8f8550044f0f755c8", "creator": "5f84e5b1d893ac42dcc9cb78", "body": "This looks cool", "createdAt": "2020-10-19T13:17:12.323Z", "updatedAt": "2020-10-19T13:17:12.323Z", "__v": 0 }, { "_id": "5f8d92e82ecfbe34b8f6375b", "creater": "5f84e5b1d893ac42dcc9cb78", "body": "hello", "createdAt": "2020-10-19T13:21:44.463Z", "updatedAt": "2020-10-19T13:21:44.463Z", "__v": 0 }, ], "_id": "5f887cef6fd7d34548a592ea", "title": "A DESCRIPTIVE PARAGRAPH EXAMPLE", "body": "\\"The room in which I found myself was very large and lofty. The windows were ", "category": "Finance", "creator": { "joined": "2020-10-15T12:14:23.888Z", "posts": [ "5f887cef6fd7d34548a592ea", "5f887e0d6fd7d34548a592ec", "5f887e266fd7d34548a592ed", "5f887e586fd7d34548a592ee", "5f89bfccc2bebd40b07b044a", "5f89c36e906bbb27b84af897", "5f89c7614199d52b141ff249", "5f89c7ea4199d52b141ff24a", "5f8c5ab175ef762ed89eddba", "5f8c5be2d7fac046f0021d9f" ], "_id": "5f88481d00ed460960da90f8", "username": "kenwaysharma", "email": "kenwaysharma@gmail.com", "password": "$2b$10$p3qjmdSKWIF9qAagZoqbjuG34cjOgXTe5XYER0aowwviIS65COVlu", "__v": 0 }, "__v": 0, "updatedAt": "2020-10-20T05:42:56.320Z" }

Here is the userDB:

 username: { type: String, required: [true, "Username is required!"], unique: true, lowercase: true, }, email:{ type: String, required: [true, "Email is required!"], unique: true, lowercase: true, validate: [isEmail, "Please enter a valid email!"] }, password:{ type: String, required: [true, "Password is required!"], minlength: [6, "Enter atleast 6 characters!"], }, comments:[{ type: mongoose.Schema.Types.ObjectId, ref: "comment" }], posts:[{ type: mongoose.Schema.Types.ObjectId, ref: "postData" }], },{timestamps : true});

GET users :

 router.get('/USERS', (req,res)=>{ User.find({}, function (err, user) { if (err) { console.log(err); }else{ res.send(user) } } ).populate('comments') .populate('posts') })

How do I get the creator data inside of comments instead of just its object ID?

Update: I also tried selecting the creator inside comments like .populate('comments', 'creator') but it still gives me the creator object ID in a string.

Update 2: I have added the code for userDB to which the commentDB and postDB references. Also added the GET users just to see how it works in postman.

Answer 1

Try chaining multiple populate methods and using the exec method to pass your callback.

posts.find({})
.populate({
   path: 'comments',
   populate: {
       path: 'creator',
       model: 'user'
   }
})
.populate('creator')
.exec(function (err, post) {
    if (err) {
      console.log(err);
    }else{
        res.json({post})
    }
});