Perform "Left/Right/Inner" joins with Mongoose - node.js

I come from an SQL background and have been finding it difficult building queries with mongoose.
I have a group schema that looks like this :
var groupSchema = new Schema({
title:{type:String, index:true, unique: true, required:true, lowercase:true}
});
and two other schemas, documents, and Users, that reference the groupSchema
User Schema:
var userSchema = new Schema({
//Other datas
group: [{type: Schema.Types.ObjectId, ref: 'Group'}],
});
Documents Schema:
var documentSchema = new Schema({
ownerId:{type:Schema.Types.ObjectId, required: true, ref:"User"},
group:{ type:Schema.Types.ObjectId, ref:"Group", required:true},
});
I would like to fetch all group data and populate them with the documents that belong to that group. I tried using the populate query but it did not work

Related

Is this the best way to design a mongodb schema?

I'm fairly new to programming, and am now at the stage where I am working on projects before starting to apply for jobs. I’m working on an express project and wanted some advice on my schema design, just in case I’m going about things in a horrible way.
The premise of the project is a desk booking app. A business administrator can create an account to register a company and add multiple offices if needed. Employees can also register as employees of a company using the unique company code and passcode, and then book desks in different offices.
This is the schema I have designed, I’ve modelled the data in this way as I want to be able to access the data in different ways e.g. an employee viewing all bookings they have made, as well as an employer viewing all bookings made in an office.
Any feedback would be much appreciated! Thanks in advance.
NB: When building the project I will have each schema in a different file, and I know I haven't required all the dependencies I will need. The purpose of this question is purely on best practices for mongoose schema design.
const mongoose = require('mongoose')
const Schema = mongoose.Schema
const CompanySchema = new Schema({
companyName: String,
companyLogo: String,
uniqueCompanyCode: String,
companyPasscode: String,
companyAdmin: [
{
type: Schema.Types.ObjectId,
ref: "User"
}
],
offices: [
{
type: Schema.Types.ObjectId,
ref: 'Office'
}
],
})
const UserSchema = new Schema({
username: {
type: String,
required: true,
unique: true
},
email: {
type: String,
required: true,
unique: true
},
bookings: [
{
type: Schema.Types.ObjectId,
ref: 'Booking'
}
]
})
UserSchema.plugin(passportLocalMongoose);
const OfficeSchema = new Schema({
officeAddress:{
streetAddress: String,
town: String,
county: String,
postcode: String
},
floorPlan: String,
desks: [
{
deskNumber: Number,
bookings:{
type: Schema.Types.ObjectId,
ref: 'Booking'
}
}
]
})
const bookingSchema = new Schema({
bookedFrom: Date,
bookedTo: Date,
bookedBy: {
type: Schema.Types.ObjectId,
ref: "User"
}
})
If you’re using the architecture of Node.js, MongoDB with mongoose, you’ll create these schemas at the beginning of every project so it’s best to get familiar with them.
This is how we create a schema in mongoose.
const mongoose = require("mongoose");
const Schema = mongoose.Schema;
let productSchema = new Schema({
name: {
type:String,
required:true
},
price: {
type:Number,
required:true
},
isAvailable: {
type:Boolean
}
});
const productModel = mongoose.model("product", productSchema);
module.exports = productModel;
The first parameter of the mongoose.model is the name of the collection that will contain the documents. The second parameter is the schema. Now, we need is to export productModel so they can be used elsewhere.
const productModel = mongoose.model("product", productSchema);
This productModel is ready to be imported and used to create data following our schema in the product collection. This is a common development pattern when using Node.js and MongoDB. An ODM-like mongoose makes managing your data more intuitive.

How to connect schemas with each other in mongooseJS?

Basically what I am trying to achieve is the following:
In my iOS application a QR-Code can be scanned to get the ID of a specific lounge and with that its JSON data (only ID and name for now) saved in MongoDB.
Every lounge is able (but doesn't have to) to add products to their lounge, so that in the end, after scanning the QR-Code, a customer is able to see which products are offered.
A product contains only a name and imageURL for now, but not a price, because the price can variate and be set by owners of a lounge. So a price of one and the same product can be different.
I would like to know, what the correct and best way is for implementing the schemas for that approach, so that I can easily fetch all products of a specific lounge, maybe based on its ID.
What I got so far:
lounge.js:
const mongoose = require('mongoose');
const loungeSchema = mongoose.Schema({
_id: mongoose.Schema.Types.ObjectId,
name: { type: String, required: true }
});
module.exports = mongoose.model('Lounge', loungeSchema);
product.js
const mongoose = require('mongoose');
const productSchema = mongoose.Schema({
_id: mongoose.Schema.Types.ObjectId,
name: { type: String, required: true },
imageURL: { type: String, required: true, unique: true }
});
module.exports = mongoose.model('Product', productSchema);
Basically you can use mongoose populate. You can achieve this by storing the products in separate collection and basically populate an array on the lounge schema using the _id for the lounge let me show you an example:
Your lounge schema would be something like this
const mongoose = require('mongoose');
const loungeSchema = mongoose.Schema({
_id: mongoose.Schema.Types.ObjectId,
name: { type: String, required: true }
products: [type: Schema.Types.ObjectId, ref: 'Products' ]
});
module.exports = mongoose.model('Lounge', loungeSchema);
And your product schema
const mongoose = require('mongoose');
const productSchema = mongoose.Schema({
_id: mongoose.Schema.Types.ObjectId,
name: { type: String, required: true },
imageURL: { type: String, required: true, unique: true }
});
module.exports = mongoose.model('Product', productSchema);
When saving creating a lounge just add the _id of the product to products array that apart of the lounge schema.
So basically you find the product and retrieve its _id.
To run a find query it would be something like this:
lounge.find({}).populate('products').exec();
products array will then have the related products for each lounge

Mongoose query from two schemas that share same reference

Suppose I have two schemas:
1. UserEnrolledCourses
var userCoursesSchema = new mongoose.Schema({
user: { type: mongoose.Schema.Types.ObjectId, ref: 'users'},
courseId: { type: mongoose.Schema.Types.ObjectId, ref: 'courses'},
isEnrolled: Boolean,
});
2. CourseResources
var resourcesSchema = new mongoose.Schema({
courseId: { type: mongoose.Schema.Types.ObjectId, ref: 'courses', required: true },
type: {type:String, required:true},
});
Both of them shared the same courseId reference from courses schema.
So, my aim is to generate result from query that for each courseId that one user enrolled, list all of the resources that available. Is that possible?
In mongoDB, you are performing queries on one concrete collection. The only exception is the left outer join with new method $lookup in aggregation for mongodb 3.2 and more. Look at documentation

Mongoose- How to reference embed document element?

I have users.js schema with a embeded document array pets. For each user, a user can have multiple pets(usually no more than 3 I would think).
For each pet, there would be a daily chart. So it would be many daily charts for a pet. I have read with embedded documents that each array element is indexed. In daily.js, how can I reference the pet it would belong to for the populate() function?
var mongoose = require('mongoose');
var Schema = mongoose.Schema;
var userSchema = new Schema({
firstName: { type: String, required: true },
lastName: { type: String, required: true },
username: { type: String, required: true, unique: true },
location: String,
pets: [{ name: 'string', animalType: 'string'}], //could have more than one pet
created_at: Date,
updated_at: Date
});
var mongoose = require('mongoose');
var Schema = mongoose.Schema;
var dailySchema = new Schema({
tite: String,
_pet: { type: Number, ref: 'User.pet' }, // not sure how to reference name in user.pets[#] array
created_at: Date,
updated_at: Date
});
Quoting
Sorry to disappoint but that is an anti-pattern. Populate can't populate from another collection's subdocs - the reason why you're getting that error is that there's no model for boards.
So it may be not good patten to reference to embedded document. It could be better to separate pet from User as one schema
var PetSchema = new Schema ({
name: 'string',
animalType: 'string'
});
And the UserSchema and DailySchema will be
var userSchema = new Schema({
...
pets: [{ type: Schema.Types.ObjectId, ref: 'Pet' }], //could have more than one pet
});
var dailySchema = new Schema({
_pet: { type: Number, ref: 'Pet' }, // not sure how to reference name in user.pets[#] array
});

Complex sort with Mongoose

I'm new in Mongoose and I want to create a 'complex' sorting. So I have the following schemas:
var UserSchema = new Schema({
firstName: String,
lastName: String,
...
skills : [{ type: Schema.Types.ObjectId, ref: 'Skill' }]
});
var ProjectSchema = new Schema({
name: String,
description: String,
...
skills : [{ type: Schema.Types.ObjectId, ref: 'Skill' }]
});
var SkillSchema = new Schema({
name: String
});
So given those schemas what I need is to sort by the matching percentage between the user skills and the project skills, so basically I want to show first the projects that are more related to the user. Is that possible by using just mongoose? If so I guess I will need to create a sorting function that I can pass to the query or something.
Thank you!

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