I've hit a wall in my server when I needed to get data from my server.
The following represents my schemas:
Schema one:{
name: String
}
Schema two:{
code:String,
name_id: refid: schema One
}
Schema three:{
phone:number
code:[refid: Schema two]
}
If I needed data from schema three, and the objects from object ids that are saved in the code array I would use populate and I would get the object referenced by object id.
Question is is it possible to populate the populated data?
If populate schema three
I would get objects such as:
{phone : 000911,
code: :{code:String,
name_id: refid: schema One}
in the previous example I want to populate the name id, is that possible?
With Mongoose, you can populate your schema with dot notation like this:
const One = new Schema({
name: String
})
const Two = new Schema({
code: String,
name: {
type: Schema.ObjectId,
ref: 'One'
}
})
const Three = new Schema({
phone: number
code: [{
type: Schema.ObjectId,
ref: 'Two'
}]
})
Three.find((err, three) => {
if (err) console.log(err)
console.log(three)
// => {
// phone : "the phone number from schema Three",
// code: {
// code: "the code from schema Two",
// name: "the name from schema One"
// }
// }
})
.populate('code.name')
Related
I am creating a express.js app and I made a database in mongoose for testing purpose. the database is inside a function seedDB() that I export to my app.js file. Creating the seed database has no error but when I add a new "review" inside of that data. it is saying cannot read property "push" of undefined even though my mongoose model is set correctly.
I have two collections inside mongoDB called "tours" and "reviews"
I tried looking up the tours inside mongo shell with db.tours.find() and I find my "review" which is an array that is associated with the review collection is set up correctly. But when I looked up db.reviews.find() . It is also there but it has about x4 result that my expected result.
I tried checking if I just forgot a parenthesis, curly brace but I think that's not the problem.
I also tried looking at my models over and over and changing again but there is also no problem
const tours = require("./models/tours");
const Review = require('./models/reviews');
let tourData = [{
image: "image.jpg",
place: "Place",
name: "name",
description: "this is a description",
price: 1234,
info: "this is a great tour"},
{
image: "image.jpg",
place: "Place",
name: "name",
description: "this is a description",
price: 1234,
info: "this is a great tour"},
{
image: "image.jpg",
place: "Place",
name: "name",
description: "this is a description",
price: 1234,
info: "this is a great tour"},
]
function seedDB(){
tours.deleteMany({}, (err)=>{
if(err){
console.log(err);
}
console.log("removed tours!");
//add a few tours
tourData.forEach(function(seeds){
tours.create(seeds, (err, data)=> {
if(err){
console.log(err)
} else {
console.log('added all tours!');
//create a comment
Review.create(
{
text: "this place is great! ",
author: "Arnold"
}, (err, comment)=> {
if(err){
console.log(err)
} else {
tours.reviews.push(comment); //why is this undefined? I set it up correctly
tours.save();
console.log("created new review")
}
});
}
});
});
});
};
module.exports = seedDB
up until console.log('added all tours!'); it is going well but when I put the Review.create(), it now has error specifically the tours.reviews.push(comment);
//tours.js model
const mongoose = require('mongoose');
var ToursSchema = new mongoose.Schema({
image: String,
place: String,
name: String,
description: String,
price: Number,
info: String,
creator: {
id: {
type: mongoose.Schema.Types.ObjectId,
ref: "User"
},
username: String
},
reviews:[
{
type: mongoose.Schema.Types.ObjectId,
ref: "Review"
}
]
});
let Tours = mongoose.model('Tour', ToursSchema);
module.exports = Tours;
reviews.js model
const mongoose = require('mongoose');
var reviewSchema = mongoose.Schema({ //I also tried doing new Mongoose.Schema({
text: String,
author: String
});
module.exports = mongoose.model('Review', reviewSchema);
expected results in console should be
removed tours!
added all tours!
added all tours!
added all tours!
created new review
created new review
created new review
and the actual results in the mongo database is have an array of reviews inside the tours collections.
Multiple things:
tours is your model, not your instance. You want to push into the reviews of one or all of your instances, which in your case is data. So in your case you can do something like data[0].reviews.push(comment). I can see how you this gut mixed up, since tours is lowercase, which makes it look like a instance, not a model.
The second worst variable name after data is data2 :-P
Consider replacing your callback with the far easier to read and maintain async/await syntax
don't directly require your models, but rather register your models and use mongoose.model('tours')
I have a mongoDB database which is generated using a script that uses only the node.js mongoDB driver without mongoose. Later on, in the application, I want to use mongoose to load a document and have a reference be populated automatically; however, this only ever returns null.
Imagine a task which contains sub-items which each have a title and an assigned person. The assigned person, in this case, is the reference I want to have populated, so the reference lives in an object inside an array in the task schema.
The following code (requiring npm install mongodb mongoose) reproduces the problem (watch out, it destroys a local database named test if you have one already):
const mongodb = require('mongodb');
const mongoose = require('mongoose');
const Schema = mongoose.Schema;
(async () => {
// Step 1: Insert data. This is done using the mongodb driver without mongoose.
const db = await mongodb.MongoClient.connect('mongodb://localhost/test');
await db.dropDatabase();
await db.collection('persons').insertOne({ name: 'Joe' });
const joe = await db.collection('persons').findOne({ name: 'Joe' });
await db.collection('tasks').insertOne({ items: [{ title: 'Test', person: joe._id }] });
await db.close();
// ================
// Step 2: Create the schemas and models.
const PersonSchema = new Schema({
name: String,
});
const Person = mongoose.model('Person', PersonSchema);
const TaskSchema = new Schema({
items: [{
title: String,
person: { type: Schema.Types.ObjectId, ref: 'Person' },
}],
});
const Task = mongoose.model('Task', TaskSchema);
// ================
// Step 3: Try to query the task and have it populated.
mongoose.connect('mongodb://localhost/test');
mongoose.Promise = Promise;
const myTask = await Task.findOne({}).populate('items.person');
// :-( Unfortunately this prints only
// { _id: "594283a5957e327d4896d135", items: [ { title: 'Test', person: null } ] }
console.log(JSON.stringify(myTask, null, 4));
mongoose.connection.close();
})();
The expected output would be
{ _id: "594283a5957e327d4896d135", items: [ { title: 'Test', person: { _id: "594283a5957e327d4896d134", name: "Joe" } } ] }
I have verified that the two _ids actually match using mongo shell:
> db.persons.find({})
{ "_id" : ObjectId("594283a5957e327d4896d134"), "name" : "Joe" }
> db.tasks.find({})
{ "_id" : ObjectId("594283a5957e327d4896d135"), "items" : [ { "title" : "Test", "person" : ObjectId("594283a5957e327d4896d134") } ] }
What am I doing wrong when attempting to populate person? I am using mongoose 4.10.6 and mongodb 2.2.28.
The answer to this problem lies in the fact that the collection name mongoose automatically infers from the model Person is people and not persons.
The problem can be solved either by writing to the people collection in the first part or by forcing mongoose to use the collection name persons:
const Person = mongoose.model('Person', PersonSchema, 'persons');
mongoose plans to remove pluralization in the collection name anyway, see #1350 on Github.
I am trying to make an API point that would do the following. I submit an Object ID in the path. The record with that ID is found. Then, the program looks into a certain field of this object. The field contains an ObjectID for another entry in the database. At last, I need to pull up that record and increment a certain field in it.
In short, I have a child->parent relationship between certain records and would like the ability of incrementing a certain field within the parent record by submitting the child's id to the API point.
Here is the code I had that did the basic child increment. How can I go about doing it for the parent?
router.get('/today/parent/up/:id', function(req, res){
var collection = db.get('Activity');
collection.update({
_id: req.params.id
},
{
$inc: {
"repetitions.today": 1,
"repetitions.total": 1
}
}, function(err, activity){
if (err) throw err;
res.json(activity);
});
})
First use mongo references, heres documenttion:
https://docs.mongodb.com/manual/reference/database-references/
here's mongoose documentation
http://mongoosejs.com/docs/2.7.x/docs/populate.html
Basically You need to do this:
var mongoose = require('mongoose')
, Schema = mongoose.Schema
var PersonSchema = new Schema({
name : String
, age : Number
, stories : [{ type: Schema.ObjectId, ref: 'Story' }]
});
var StorySchema = new Schema({
_creator : { type: Schema.ObjectId, ref: 'Person' }
, title : String
, fans : [{ type: Schema.ObjectId, ref: 'Person' }]
});
var Story = mongoose.model('Story', StorySchema);
var Person = mongoose.model('Person', PersonSchema);
Then you could use .populate() method, and then you could extract your populated model and make changes and save them with .save(), but remember to use it in populated model, not the parent one. For ex. You've got author which contains reference to books, so you make request
author.findOne({'name': 'King'}).populate('books').exec((err, king) => {
let book0 = king.books[0];
book0.title = 'I need to change this one';
book0.save((err, data) => {
console.log('saved referenced object')
}
})
We have a requirement to store a copy of a Mongo document, as an embedded subdocument in another document. It should have a reference to the original document. The copied document needs to be a deep copy, like a snapshot of the original.
The original document's schema (defined with Mongoose) is not fixed -
it currently uses a type of inheritance to allow different additions to the Schema depending on "type".
Is there a way to such a flexible embedded schema within a Mongoose model?
Is it something that needs to be injected at runtime, when we can know
the schema?
The models / schemas we have currently look like this:
///UserList Schema: - this should contain a deep copy of a List
user: {
type: ObjectId,
ref: 'User'
},
list: {
/* Not sure if this is a how we should store the reference
type: ObjectId,
ref: 'List'
*/
listId: ObjectId,
name: {
type: String,
required: true
},
items: [{
type: ObjectId,
ref: 'Item'
}]
}
///List Schema:
name: {
type: String,
required: true
},
items: [{
type: ObjectId,
ref: 'Item'
}],
createdBy: {
type: ObjectId,
ref: 'User'
}
The code we currently have uses inheritance to allow different item types. I realise this technique may not be the best way to achieve the flexibility we require and is not the focus of my question.
///Item Model + Schema
var mongoose = require('mongoose'),
nodeutils = require('util'),
Schema = mongoose.Schema,
ObjectId = Schema.Types.ObjectId;
function ItemSchema() {
var self = this;
Schema.apply(this, arguments);
self.add({
question: {
type: String,
required: true
}
});
self.methods.toDiscriminator = function(type) {
var Item = mongoose.model('Item');
this.__proto__ = new Item.discriminators[type](this);
return this;
};
}
nodeutils.inherits(ItemSchema, Schema);
module.exports = ItemSchema;
I think you just need to create an empty {} object for the document in your parent mongoose schema. This way you´ll be able to store any object with a hardcopy of all it´s data.
parentobj : {
name: Sring,
nestedObj: {}
}
I think at this point, what you´ll need is to mark your nested objet as modified before you save it. Here is an example of my mongoose code.
exports.update = function(req, res) {
User.findById(req.params.id, function (err, eluser) {
if (err) { return handleError(res, err); }
if(!eluser) { return res.send(404); }
var updated = _.merge(eluser, req.body);
//This makes NESTEDDATA OBJECT to be saved
updated.markModified('nestedData');
updated.save(function (err) {
if (err) { return handleError(res, err); }
return res.json(200, eluser);
});
});
};
In addition, if you need an array of different documents in nestedDocument, the right way is this one:
parentobj : {
name: Sring,
nestedObjs: [Schema.Types.Mixed]
}
Please check Mongoose Schema Types carefully
EDIT
As you said, I´ll add you final solution as including ItemSchema in the nestedObj array definition to clarifythe type of the object to a determined one..
var ItemSchema = new Schema({
item1: String,
item2: String
});
var parentobj = new Schema({
name: Sring,
nestedObj: [ItemSchema]
});
EDIT 2:
Remember adding new Items to the nestedArray, must be done with nestedArray.push(item)
regards!!
I'm currently trying to develop an app using mongo and node.js.
I am facing a problem when I want to build a query who use the populate option.
Here are my Schemas :
// Schema used by mongoose
var userSchema = new mongoose.Schema(
{
_id: mongoose.Schema.Types.ObjectId,
login: String,
password: String,
movies: [ { type: mongoose.Schema.Types.ObjectId, ref: movieModel} ],
admin: Boolean
},{ collection: "user" });
var movieSchema = new mongoose.Schema(
{
_id: mongoose.Schema.Types.ObjectId,
title: String,
}, { collection: "movie" });
As you can see, each user have an array of movies, this array contains valid ids of movies. What I want is to have the movies of an user. This is how I build my query :
var query = userModel.findOne({ login: req.session.user["login"] })
.populate("movies");
query.exec(function(err, user)
{
if (err)
throw err;
console.log(user.movies[0].title);
});
The query is executed successfully, but when I try to display the title of the first movie at the console.log line I got an error "TypeError: Cannot read property 'title' of undefined". I checked the documentation of mongoose and don't understand why I'm getting this error.
I would like to specify that my database contains valid data.
I put mongoose in debug mode, and this is the query that is executed :
Mongoose: user.findOne({ login: 'user' }) { fields: undefined }
Mongoose: user.find({ _id: { '$in': [ ObjectId("52e2a28949ad409834473e71"), ObjectId("52e2a28949ad409834473e79") ] } }) { fields: undefined }
The two ids on the second line are valid ids of movies. I would like to display their name.
Thanks a lot for your help.
What is the value of this: ref: movieModel?
movieModel would need to be set to the string like "Movie". See here for more information. It will need to match the identifier provided when you create the Movie model.
var Movie = mongoose.model('Movie', movieSchema);
So, you might have in a schema:
var userSchema = mongoose.Schema({
name: String,
favorite_movies: { type: Schema.Types.ObjectId, ref: 'Movie' }
});
var User = mongoose.model('User', userSchema);
I've used the string Movie in both the Schema definition and when creating the Movie type. They need to be exactly the same.
MongooseJs uses the string name of the Model to determine where to fetch the documents from when using ref and populate.
In the debug output, you can see how Mongoose is actually querying the wrong collection, as I'd expect it to be using movies.find to find the relevant Movie documents.