I'm new to MongoDb and Mongoose and this might sound silly but I'm a bit confused about how things work.
I have two unrelated models: page model and team model that looks something like this:
// page.js
const mongoose = require('mongoose');
const schema = new mongoose.schema({
name: String,
body: {
title: String,
},
});
const Page = mongoose.model('Page', schema);
export default Page;
and
// team.js
const mongoose = require('mongoose');
const schema = new mongoose.schema({
name: String,
position: Number,
});
const Team = mongoose.model('Team', schema);
export default Team;
What I want to do is when I find one page (Page.findOne({...})) to include all teams. The result will look like this:
{
_id: 'some_id',
name: 'some name',
body: {
title: 'A title',
teams: [
{ name: 'Team1', position: 1 },
{ name: 'Team2', position: 2 },
// ...
{ name: 'Team3', position: 3 },
],
},
}
I looked at populate but this requires refs to other model.
Looked at virtuals but from what I understand this should work only with instance properties.
What will be the best approach to achieve this without adding relations between the two models?
This is I'm currently doing:
const pageResult = await Page.findOne({});
let page = pageResult.toObject();
page.body.team = await Team.find({});
well with out referencing, the only way to do that is to manually query Page model and findOne() what is the doc you want and then inside the callback of that findOne(), you will have to get Teams you desire with the value of Page.body.title value.
But its very easy to use Ref and populate using mongoose but if this is the way you really want to go knock yourself out mate ... :) cheers ...
Page.findOne({_id:req.body.id},(err,page)=>{
if(!err){
team.find({},(err,teams)=>{ // this will give you an array of teams
if(!err){
page.body.teams = teams; // this line set teams array from this callback to previous findOne()'s page obj
//so that you will finally create the object you want
}else{
throw err;
}
});
}else{
}
});
since you have only 2 fields in team model I think you won't be needing to use projections
I'm trying to add the ID of my category documents to my budget documents. Below is the Schema for my budgets.
var {mongoose} = require('../db/mongoose');
var budgetsSchema = new mongoose.Schema({
year: Number,
categoryIDs: [{type:mongoose.Schema.ObjectId,
ref: 'categories'}]
});
var Budgets = mongoose.model('Budgets', budgetsSchema);
module.exports = {
Budgets
};
And here is the Schema for my categories collection.
var {mongoose} = require('../db/mongoose');
var categorySchema = mongoose.Schema({
name: String,
amount: Number,
sub_categories: [{
name: String,
amount: Number
}]
})
var categories = mongoose.model('categories', categorySchema);
module.exports = {
categories
};
To post categories, I use this express post request to add the categories to the category collection and its ID to the Budget collection.
//The ID is the Budget ID
app.post('/categories/:id', (req, res) => {
var id = req.params.id;
var sub_categories = req.body.sub_categories;
var category = new categories({
name: req.body.name,
amount: req.body.amount,
sub_categories
})
category.save().then((docs) => {
res.send(docs);
console.log(docs)
}).catch((e) => res.status(404).send(e));
Budgets.findById(id).then((docs) => {
if(!docs) {
res.status(404).send();
}
docs.categoryIDs.push(category._id);
}).catch((e) => {
res.send(e).status(404);
})
})
When I run this, it does add the category to the collection, but it does not add the ID to the categoryIDs array in the Budget document. Please help
First, change the model name from Plural to Singular as mentioned in the mongoose docs to avoid confusion:
The first argument is the singular name of the collection your model
is for. Mongoose automatically looks for the plural version of your
model name. Thus, for the example above, the model Tank is for the
tanks collection in the database. The .model() function makes a copy
of schema. Make sure that you've added everything you want to schema
before calling .model()!
So categories to Category and Budgets to Budget. Please verify the new before mongoose.model here, Mongoose docs ref.
var categorySchema = new mongoose.Schema({
name: String,
amount: Number,
sub_categories: [{
name: String,
amount: Number
}]
})
for example the nexts schemas are in diferent folders like these:
cr/user
lms/content
this is the schemaContent
user: {
type: Schema.Types.ObjectId,
ref: 'cr/user'
}
How can I ref user from Content?
because when I used cr/user I get an error "Schema hasn't been registered for model"
I need just populate user from content like Content.find().populate({ path: 'users' }) Keeping user in the folder called cr and content in the folder called lms
You are trying to nest documents. Try below approach to nest document.
i will assume the directories cr and lms are inside the directory called demoproject
demoproject/cr/user.js
const mongoose = require("mongoose");
const Schema = mongoose.Schema;
const UserSchema = new Schema({
name:{
type : String,
required: true
}
});
const User = mongoose.model("User",UserSchema);
module.exports = User;
demoproject/lms/content.js
./../cr/user - go back from lms directory and get into cr/user
const mongoose = require("mongoose");
const Schema = mongoose.Schema;
const User = require("./../cr/user");
const ContentSchema = new Schema({
type:{
type : String,
required: true
},
users : [{
type : Schema.Types.ObjectId,
ref : "User"
}]
});
const Content = mongoose.model("Content",ContentSchema);
module.exports = Content;
How can I ref user from Content?
i hope your question is clear now. Keep reading below
Moment of truth
Lets insert data by using these two models.
Create a file to write mongo queries (demoproject/index.js).
As User model is nested into Content model, we need to first save data into User model
Then save data into Content model
Now push data into users object present in Content Model contentdata.users.push(userdata);
Donot forget to save the contentdata after pushing the userdata object into contentdata contentdata.save();
demoproject/index.js
const User = require("./cr/user");
const Content = require("./lms/content");
const userobj = new User({name : "rockyjohnson"});
const contentobj = new Content({type : "gloves"});
userobj.save().then((userdata)=>{
contentobj.save().then((contentdata)=>{
contentdata.users.push(userdata);
contentdata.save();
}).catch((err)=>{
console.log("err while saving contentdata ", err);
})
}).catch((err)=>{
console.log("err while saving userdata ", err);
})
Mongodb output
That is all
Update: answer for the second question
find returns an array object in its promise. i'm able to extract users object present inside Content model here. Below is the query i used to verify
Content.find().then((data)=>{
data.forEach(element => {
console.log("element users ",element.users); // element.users contains all id's stored in the users array
});
}).catch((err)=>{
console.log("err ",err);
})
This is my players model
var mongoose = require('mongoose'),Schema = mongoose.Schema;
var playerSchema = Schema({
name: String,
password: String,
country: String
});
mongoose.model('players', playerSchema);
This is my countries model
var mongoose = require('mongoose'),Schema = mongoose.Schema;
var countrySchema = Schema({
name: String,
isActive: Boolean
});
mongoose.model('countries', countrySchema);
And this is app.js
mongoose.model('players').find({}, function (err, players) {
console.log(players);
if (err) {
return console.error(err);
} else {
res.format({
html: function(){
res.render('players/index', {
title: 'Players List',
"players" : players
});
},
json: function(){
res.json(players);
}
});
}
});
In players model I have countryId and in countries model I have corresponding countryName. Now I want to find players with country name with same find() query.
you can use mongoose populate method
refer this link: mongoose populate
in your example, it something like this:
mongoose.model('players').find().populate('country').exec(function(err,players){
});
this will give you result of both countryID and Name
mongodb is nosql-database, not a relational database like mysql/postgre. So modelling your data is not like relationaldatabses where you can make one query that joins two tables (in mongodb, "tables" are called collections).
In MongoDB and your current Schema you will first need to find the countryId of the country you want. And then find the players that have that country.
Alternatives;
you can store the countryName directly on the player collection
you can store the playerId's in an array within the the country collection
further more, in your playerSchema, country should be a ObjectId, not a String.
I want to give users the ability to create collections in my Node app. I have really only seen example of hard coding in collections with mongoose. Anyone know if its possible to create collections dynamically with mongoose? If so an example would be very helpful.
Basically I want to be able to store data for different 'events' in different collections.
I.E.
Events:
event1,
event2,
...
eventN
Users can create there own custom event and store data in that collection. In the end each event might have hundreds/thousands of rows. I would like to give users the ability to perform CRUD operations on their events. Rather than store in one big collection I would like to store each events data in a different collection.
I don't really have an example of what I have tried as I have only created 'hard coded' collections with mongoose. I am not even sure I can create a new collection in mongoose that is dynamic based on a user request.
var mongoose = require('mongoose');
mongoose.connect('localhost', 'events');
var schema = mongoose.Schema({ name: 'string' });
var Event1 = mongoose.model('Event1', schema);
var event1= new Event1({ name: 'something' });
event1.save(function (err) {
if (err) // ...
console.log('meow');
});
Above works great if I hard code 'Event1' as a collection. Not sure I create a dynamic collection.
var mongoose = require('mongoose');
mongoose.connect('localhost', 'events');
...
var userDefinedEvent = //get this from a client side request
...
var schema = mongoose.Schema({ name: 'string' });
var userDefinedEvent = mongoose.model(userDefinedEvent, schema);
Can you do that?
I believe that this is a terrible idea to implement, but a question deserves an answer. You need to define a schema with a dynamic name that allows information of 'Any' type in it. A function to do this may be a little similar to this function:
var establishedModels = {};
function createModelForName(name) {
if (!(name in establishedModels)) {
var Any = new Schema({ any: Schema.Types.Mixed });
establishedModels[name] = mongoose.model(name, Any);
}
return establishedModels[name];
}
Now you can create models that allow information without any kind of restriction, including the name. I'm going to assume an object defined like this, {name: 'hello', content: {x: 1}}, which is provided by the 'user'. To save this, I can run the following code:
var stuff = {name: 'hello', content: {x: 1}}; // Define info.
var Model = createModelForName(name); // Create the model.
var model = Model(stuff.content); // Create a model instance.
model.save(function (err) { // Save
if (err) {
console.log(err);
}
});
Queries are very similar, fetch the model and then do a query:
var stuff = {name: 'hello', query: {x: {'$gt': 0}}}; // Define info.
var Model = createModelForName(name); // Create the model.
model.find(stuff.query, function (err, entries) {
// Do something with the matched entries.
});
You will have to implement code to protect your queries. You don't want the user to blow up your db.
From mongo docs here: data modeling
In certain situations, you might choose to store information in
several collections rather than in a single collection.
Consider a sample collection logs that stores log documents for
various environment and applications. The logs collection contains
documents of the following form:
{ log: "dev", ts: ..., info: ... } { log: "debug", ts: ..., info: ...}
If the total number of documents is low you may group documents into
collection by type. For logs, consider maintaining distinct log
collections, such as logs.dev and logs.debug. The logs.dev collection
would contain only the documents related to the dev environment.
Generally, having large number of collections has no significant
performance penalty and results in very good performance. Distinct
collections are very important for high-throughput batch processing.
Say I have 20 different events. Each event has 1 million entries... As such if this is all in one collection I will have to filter the collection by event for every CRUD op.
I would suggest you keep all events in the same collection, especially if event names depend on client code and are thus subject to change. Instead, index the name and user reference.
mongoose.Schema({
name: { type: String, index: true },
user: { type: mongoose.Schema.Types.ObjectId, ref: 'User', index: true }
});
Furthermore I think you came at the problem a bit backwards (but I might be mistaken). Are you finding events within the context of a user, or finding users within the context of an event name? I have a feeling it's the former, and you should be partitioning on user reference, not the event name in the first place.
If you do not need to find all events for a user and just need to deal with user and event name together you could go with a compound index:
schema.index({ user: 1, name: 1 });
If you are dealing with millions of documents, make sure to turn off auto index:
schema.set('autoIndex', false);
This post has interesting stuff about naming collections and using a specific schema as well:
How to access a preexisting collection with Mongoose?
You could try the following:
var createDB = function(name) {
var connection = mongoose.createConnection(
'mongodb://localhost:27017/' + name);
connection.on('open', function() {
connection.db.collectionNames(function(error) {
if (error) {
return console.log("error", error)
}
});
});
connection.on('error', function(error) {
return console.log("error", error)
});
}
It is important that you get the collections names with connection.db.collectionNames, otherwise the Database won't be created.
This method works best for me , This example creates dynamic collection for each users , each collection will hold only corresponding users information (login details), first declare the function dynamicModel in separate file : example model.js
/* model.js */
'use strict';
var mongoose = require('mongoose'),
Schema = mongoose.Schema;
function dynamicModel(suffix) {
var addressSchema = new Schema(
{
"name" : {type: String, default: '',trim: true},
"login_time" : {type: Date},
"location" : {type: String, default: '',trim: true},
}
);
return mongoose.model('user_' + suffix, addressSchema);
}
module.exports = dynamicModel;
In controller File example user.js,first function to create dynamic collection and second function to save data to a particular collection
/* user.js */
var mongoose = require('mongoose'),
function CreateModel(user_name){//function to create collection , user_name argument contains collection name
var Model = require(path.resolve('./model.js'))(user_name);
}
function save_user_info(user_name,data){//function to save user info , data argument contains user info
var UserModel = mongoose.model(user_name) ;
var usermodel = UserModel(data);
usermodel.save(function (err) {
if (err) {
console.log(err);
} else {
console.log("\nSaved");
}
});
}
yes we can do that .I have tried it and its working.
REFERENCE CODE:
app.post("/",function(req,res){
var Cat=req.body.catg;
const link= req.body.link;
const rating=req.body.rating;
Cat=mongoose.model(Cat,schema);
const item=new Cat({
name:link,
age:rating
});
item.save();
res.render("\index");
});
I tried Magesh varan Reference Code ,
and this code works for me
router.post("/auto-create-collection", (req, res) => {
var reqData = req.body; // {"username":"123","password":"321","collectionName":"user_data"}
let userName = reqData.username;
let passWord = reqData.password;
let collectionName = reqData.collectionName;
// create schema
var mySchema = new mongoose.Schema({
userName: String,
passWord: String,
});
// create model
var myModel = mongoose.model(collectionName, mySchema);
const storeData = new myModel({
userName: userName,
passWord: passWord,
});
storeData.save();
res.json(storeData);
});
Create a dynamic.model.ts access from some where to achieve this feature.
import mongoose, { Schema } from "mongoose";
export default function dynamicModelName(collectionName: any) {
var dynamicSchema = new Schema({ any: Schema.Types.Mixed }, { strict: false });
return mongoose.model(collectionName, dynamicSchema);
}
Create dynamic model
import dynamicModelName from "../models/dynamic.model"
var stuff = { name: 'hello', content: { x: 1 } };
var Model = await dynamicModelName('test2')
let response = await new Model(stuff).save();
return res.send(response);
Get the value from the dynamic model
var Model = dynamicModelName('test2');
let response = await Model.find();
return res.send(response);