I have two collections as follows :
This is my vehicle schema
const VehicleSchema = new schema({
user: {
type: schema.Types.ObjectId,
ref: "users"
},
name: {
type: String,
required: true
},
brand: {
type: String,
required: true
},
plate: {
type: String,
required: true
},
IMEI: {
type: String,
required: true
}
});
This is my Trip schema
const TripSchema = new schema({
date: {
type: Date,
default: Date.now
},
IMEI: String,
data: [
{
lat: String,
lon: String
}
]
});
Trip and Vehicle schemas share the the key IMEI, so when the user is logged in I wanna grab the trips based on the IMEI number, what is the most efficient way to approach this problem ? here is a look at my router
router.get(
"/",
passport.authenticate("jwt", { session: false }),
(req, res) => {
Vehicles.find({ user: req.user.id }).then(vehicles => {
if (!vehicles) {
return res.json({ error: "you do not have any vehicles yet" });
}
Trips.find().then(trips => {
// ??
});
});
}
);
You can simply do a $lookup and do a left join on trips with vehicles:
db.vechicles.aggregate([
{
$lookup:
{
from: "trips",
localField: "IMEI",
foreignField: "IMEI",
as: "trips"
}
}
])
This should get you what you want in one call.
Note this is available in mongodb versions 3.2+
Related
I am facing a problem while making a relation between two collections (I am using MEAN stack)
I have two collections: Books and Authors
In frontend I want to make a CRUD menu, where I add a new book in the table and then from there i insert a few data about book and then I choose author from the dropdown menu (fetchin data from Authors collection)
So at the end my Book collection needs to have a few data about the book and then inside the object i need an array of data about those author.
Book schema:
const BookSchema = new mongoose.Schema({
owner: { type: String, required: true },
pagesNo: { type: String, required: true },
releaseDate: { type: String, required: true },
country: { type: String, required: true },
authorID: { type: String, required: true }, <-- HERE I NEED DATA ABOUT AUTHOR
});
Author schema:
const AuthorSchema = new mongoose.Schema({
name: { type: String, required: true },
surname: { type: String, required: true },
dateOfBirth: { type: String, required: true },
countryOfBirth: { type: String, required: true },
});
Book route: book.ts
router.get("/", async (req, res) => {
try {
const books= await Book.find();
let Author = await Author.find({
books: { $elemMatch: { _id: books.bookID } },
});
res.status(200).json(books);
} catch (err) {
res.status(404).json({ success: false, msg: "Booknot found" });
}
});
The problem is somewhere inside the find() function.. Is it even a good practice? I want that it can handle a lot of data.
Thanks to everyone!
Greetings.
Your Book schema would be like this:
const MongooseSchema = new mongoose.Schema({
owner: {
type: String,
required: true,
},
pagesNo: {
type: String,
required: true,
},
releaseDate: {
type: String,
required: true,
},
country: {
type: String,
required: true,
},
authorId: {
type: mongoose.Schema.ObjectId,
ref: 'User',
required: true,
},
});
And your Author Schema would remain the same (in order to link both schemas).
Your route would be like this (if you want to search all books along with their author names):
router.get('/', async (req, res) => {
try {
const books = await Book.find().populate('authorId');
res.status(200).json(books);
} catch (err) {
res.status(404).json({ success: false, msg: 'Booknot found' });
}
});
And in case you want to search for books with a specific author id then your route would be like this:
router.get('/', async (req, res) => {
try {
const books = await Book.find({ authorId }).populate('authorId');
res.status(200).json(books);
} catch (err) {
res.status(404).json({ success: false, msg: 'Booknot found' });
}
});
AuthorID should be type ObjectId, not string.
To join data from other table, you have to use an aggregate with a lookup.
let author = await Author.aggregate([
{
$lookup:
{
from: "books",
localField: "_id",
foreignField: "authorID",
as: "books"
}
}
]);
I'm work with an user/articles profile system. I have been using the .populate() to render the posts but I cannot get the articles sorted by the date they were created.
I am using the createdAt variable as the main way of ordering the posts displayed.
For reference:
router.get('/:id', async (req, res) => {
const user = await User.findById(req.params.id, function(error) {
if(error) {
req.flash("error", "something went wrong")
res.redirect("/");
}
}).populate('articles')
res.render('users/show',{
user: user
});
and the article.js:
const ArticleSchema = new mongoose.Schema({
title: {
type: String,
required: true
},
author: {
type: String
},
markdown: {
type: String,
required: true
},
createdAt: {
type: Date,
default: Date.now
},
slug: {
type: String,
required: true,
unique: true
},
sanitizedHtml: {
type: String,
required: true
},
img: {
type: String
},
type:{
type: String
},
user : { type: Schema.Types.ObjectId, ref: 'User' },
}, {timestamps: true});
In advance thank you all for the help.
There is a property called options in populate,
.populate({
path: 'articles',
options: { sort: { createdAt: -1 } }
})
THIS PROBLEM IS A LITTLE LONGER. SO I TYPED BOLD THE CRITICAL INFORMATIONS FOR YOU.
I develop a project like stackoverflow. I have 4 databases which are:
problems
users
solutions
comments
I referrenced these schemas each other. Here is the Schemas:
Problem Schema
const problemSchema = new mongoose.Schema({
title: {
type: String,
required: [true, 'You have to enter a title']
},
content: {
type: String,
required: [true, 'You have to enter a content']
},
createdAt: {
type: Date,
default: Date.now()
},
slug: {
type: String
},
solution: [
{
type: mongoose.Schema.Types.ObjectId,
ref: 'Solution'
},
],
comment: [
{
type: mongoose.Schema.Types.ObjectId,
ref: 'Comment'
}
],
votes: {
type: Number,
default: 0
},
views: {
type: Number,
default: 0
},
user: {
type: mongoose.Schema.Types.ObjectId,
required: true,
ref: 'User'
}
})
module.exports = mongoose.model('Problem', problemSchema)
User Schema:
const userSchema = new mongoose.Schema({
name: {
type: String,
required: true
},
email: {
type: String,
required: [true, 'You have to enter an email'],
unique: true,
match: [
/^([\w-\.]+#([\w-]+\.)+[\w-]{2,4})?$/,
'Please provide a valid email address.'
]
},
password: {
type: String,
required: [true, 'You have to enter a password'],
minlength: [6, 'Your password cannot be less than 6 character.'],
select: false
},
role: {
type: String,
default: 'user',
enum: ['user', 'admin']
},
createdAt: {
type: Date,
default: Date.now()
},
about: {
type: String
},
place: {
type: String
},
age: {
type: Number
},
blocked: {
type: Boolean,
default: false
},
problem: [
{
type: mongoose.Schema.Types.ObjectId,
ref: 'Problem'
},
],
solution: [
{
type: mongoose.Schema.Types.ObjectId,
ref: 'Solution'
}
],
comment: [
{
type: mongoose.Schema.Types.ObjectId,
ref: 'Comment'
}
]
})
and Comments Schema:
const commentSchema = new mongoose.Schema({
content: {
type: String,
required: [true, 'You have to enter a content']
},
createdAt: {
type: Date,
default: Date.now()
},
isFunctional: {
type: Boolean,
default: false
},
user: {
type: mongoose.Schema.Types.ObjectId,
required: true,
ref: 'User'
},
problem: {
type: mongoose.Schema.Types.ObjectId,
ref: 'Problem'
},
})
module.exports = mongoose.model('Comment', commentSchema)
In my project, I send problems into MongoDB. Then I send comment. After save comments, I add these comments into problems and user DB with a function.
function that comments are saved in DB:
const Comment = require('../models/comment/Comment')
const Problem = require('../models/problem/Problem')
const User = require('../models/user/User')
const asyncErrorWrapper = require('express-async-handler')
const addCommentToProblem = asyncErrorWrapper(async (req, res, next) => {
const {content, problemId} = req.body
const newComment = await Comment.create({
content: content,
problem: problemId,
user: req.user.id,
})
const problemOfComment = await Problem.findByIdAndUpdate(problemId, {
$push: { comment: newComment._id }
})
const userOfComment = await User.findByIdAndUpdate(req.user.id, {
$push: { comment: newComment._id }
})
})
Okey everything is so far so good. The problem comes here. When I try to get a problem, I populate some fields for example user fields. So I can add user information in this detail of problem. When populate user and comment in problem schema, it sends me the data. Still, we're ok. But when I try to get user field in comments, it doesn't populate user. It turns just objectId of user information.
Here is the function that I get problem:
const getAProblem = asyncErrorWrapper(async (req, res, next) => {
const {id} = req.params
const problems = null
await Problem.findByIdAndUpdate(id, {
$inc: { views: 1 }
}, { new: true })
.populate('user') ==> THIS LINE WORKS
.populate('comment') ==> THIS LINE WORKS
.populate('comment.user') ==> THIS LINE DOES NOT WORK
.exec(function(err, post) {
if(err) {
console.log(err)
}
res
.status(200)
.json({
success: true,
data: post
})
});
})
Thanks for reading and your patience. Any help will be appreciated.
See doc at https://mongoosejs.com/docs/populate.html
And try this way.
const getAProblem = asyncErrorWrapper(async (req, res, next) => {
const {id} = req.params
const problems = null
await Problem.findByIdAndUpdate(id, {
$inc: { views: 1 }
}, { new: true })
.populate('user') ==> THIS LINE WORKS
.populate({
'path': 'comment',
'populate': {
'path':'user'
}
})
.exec(function(err, post) {
if(err) {
console.log(err)
}
res
.status(200)
.json({
success: true,
data: post
})
});
})
In this I am using nodejs with express and mongoose. My question is how does changing the secondaryUser field affect whether or not the findOne works? If I have it as friends.id it works and it finds the right profile, but I want to tie it to the user field in the profile. If I change it to friends.user.id the findOne fails and it sends the 404 error in the catch.
router.post(
"/:handle",
passport.authenticate("jwt", {
session: false
}),
(req, res) => {
Profile.findOne({ handle: req.params.handle }).then(friends => {
const newFriend = new Friend({
initialAccepted: true,
initialUser: req.user.id,
secondaryUser: friends.id
});
newFriend
.save()
.then(Friend => res.json(Friend))
.catch(err =>
res.status(404).json({
friendnotfound: "No people found with that handle"
})
);
});
}
);
The schema used for friend is
const FriendSchema = new Schema({
initialUser: {
type: Schema.Types.ObjectId,
ref: "profile"
},
secondaryUser: {
type: Schema.Types.ObjectId,
ref: "profile"
},
initialAccepted: {
type: Boolean,
default: false
},
initialSecondary: {
type: Boolean,
default: false
},
date: {
type: Date,
default: Date.now()
}
});
This is the schema for the profile
const ProfileSchema = new Schema({
user: {
type: Schema.Types.ObjectId,
ref: "users"
},
handle: {
type: String,
required: true,
max: 40
},
bio: {
type: String
},
platforms: {
type: [String]
},
website: {
type: String
},
social: {
youtube: {
type: String
},
twitter: {
type: String
},
facebook: {
type: String
},
linkedin: {
type: String
},
twitch: {
type: String
}
},
games: [
{
name: {
type: String
},
platform: {
type: String
},
handle: {
type: String
},
rank: {
type: String
}
}
],
date: {
type: Date,
default: Date.now
}
});
Follow proper naming convention for variables
Profile.findOne({ handle: req.params.handle }).then(profile => { // changed name from friends to profile
const newFriend = new Friend({
initialAccepted: true,
initialUser: req.user.id,
secondaryUser: profile.id // changed name from friends to profile
// profile.user.id (ref to user table not provided in schema)
});
if you give profile.user.id the object will not get created ( checking for id inside profile schema but user id provided)
Friend Schema:
secondaryUser: {
type: Schema.Types.ObjectId,
ref: "profile" // checking for id inside profile schema
},
I have a item model where it a virtual field to refer stock badges.
'use strict';
const mongoose = require('mongoose');
const mongooseHidden = require('mongoose-hidden')();
const Badge = mongoose.model('Badge');
const validateProperty = function(property) {
return (property.length);
};
const Schema = mongoose.Schema;
const ItemSchema = new Schema({
itemCode: {
type: Number,
index: {
unique: true,
sparse: true // For this to work on a previously indexed field, the index must be dropped & the application restarted.
},
required: true
},
itemName: {
type: String,
uppercase: true,
trim: true
},
barcode: {
type: String,
trim: true
},
category: {
type: Schema.Types.ObjectId,
ref: 'Category'
},
subCategory: {
type: Schema.Types.ObjectId,
ref: 'SubCategory'
},
updated: {
type: Date
},
created: {
type: Date,
default: Date.now
},
status: {
type: String,
enum: [
'active', 'inactive', 'removed'
],
default: 'active'
}
}, {id: false});
ItemSchema.virtual('badges').get(function() {
return this.getAvailableBadges();
});
ItemSchema.methods.getAvailableBadges = function() {
Badge.find({
item: this._id
}, (err, badges) => {
if (badges) {
return badges;
} else {
return [];
}
});
};
ItemSchema.set('toJSON', {virtuals: true});
ItemSchema.set('toObject', {virtuals: true});
ItemSchema.plugin(mongooseHidden, {
hidden: {
_id: false,
__v: true
}
});
mongoose.model('Item', ItemSchema);
And batch model as below
'use strict';
const mongoose = require('mongoose');
const mongooseHidden = require('mongoose-hidden')();
const validateProperty = function(property) {
return (property.length);
};
const Schema = mongoose.Schema;
const BadgeSchema = new Schema({
item: {
type: Schema.Types.ObjectId,
ref: 'Item'
},
qty: {
type: Number,
validate: [validateProperty, 'Please enter Quantity !']
},
purchasingPrice: {
type: Number,
validate: [validateProperty, 'Please enter purchasingPrice !']
},
sellingPrice: {
type: Number,
validate: [validateProperty, 'Please enter sellingPrice !']
},
updated: {
type: Date
},
created: {
type: Date,
default: Date.now
},
status: {
type: String,
enum: [
'active', 'inactive', 'removed'
],
default: 'active'
}
});
BadgeSchema.plugin(mongooseHidden, {
hidden: {
_id: false,
__v: true
}
});
mongoose.model('Badge', BadgeSchema);
Item's badge virtual field doesn't got populated.
How are we going to work with async getter method
I have put some console log statements and found that getAvailableBadges is getting data.
I need to send json object with virtual field values via express. How to I do it?
What I did was create an virtual property
ItemSchema.virtual('badges', {
ref: 'Badge',
localField: '_id',
foreignField: 'item'
});
And populate it with
{
path: 'badges',
select: [
'qty', 'purchasingPrice', 'sellingPrice'
],
options: {
sort: {
'created': -1
}
}
}
Well, the operations are asynchronous so you have to wait for the callback to fire.
You can only return the values by passing it in the callback (or you can set the values of the current object prior to calling the callback).
I think it would be something like this:
ItemSchema.virtual('badges').get(function (callback) {
Badge.find({ item: this._id }, callback);
};
Then you would use it like
item.badges(function (err, badges) {
// do something with badges
});