CODEWITHSUNDEEP
javascriptnode.jsjsonmongodb
Parzival
Parzival

Reputation: 329

How to generate unique id for each entry in mongoDB?

How do I generate a unique ID for each entry into my mongoDB through Postman?

I run postman POST with http://localhost:8000/api/user/store and send

{
"name":"testname",
"email":"[email protected]",
"phone":"testnumber",
"city":"testcity",
}

This gets saved in my mongoDB and shows this in my mongoDB compass

_id:61f7e48f0c651345677b7775
name:"testname"
email:"[email protected]"
phone:"testnumber"
city:"testcity"
__v:0

How can I generate a unique ID and add it in between this process such that it gets saved something like this:

_id:61f7e48f0c651345677b7775
uniqueID:68465135
name:"testname"
email:"[email protected]"
phone:"testnumber"
city:"testcity"
__v:0

My model userData.js looks like this:

const mongoose = require('mongoose');
const Schema = mongoose.Schema;

const userSchema = new Schema({
    name: {
        type: String,
        required: true
    },
    email: {
        type: String,
        required: true
    },
    phone: {
        type: String,
        required: true
    },
    city: {
        type: String,
        required: true
    },
}, { timeStamps: true })

const User = mongoose.model('User', userSchema);
//export model to use in other files
module.exports = User;

This is the snippet from UserController.js on how the data gets saved

// Saves user to the database
const store = (req, res, next) => {
    let user = new User({
        name: req.body.name,
        email: req.body.email,
        phone: req.body.phone,
        city: req.body.city,
    })
    user.save()
        .then(response => {
            res.json({
                message: 'User added successfully!'
            })
        })
        .catch(error => {
            res.json({
                message: 'An error occured!'
            })
        })
}

The uniqueID can be anything I just added numeric as example. But it has to be unique. How can I do this? Any suggestions would be helpful.

Upvotes: 2

Views: 22089

Answers (4)

Lucjan Grzesik
Lucjan Grzesik

Reputation: 779

You can use _id from MongoDB as it will always be unique if you don't like the format of the MongoDB _id you can change it to nanoid.

Model

With new uniqueId field

import { nanoid } from 'nanoid';

const UserSchema = new mongoose.Schema({
  name: string,
  uniqueId: {
    type: String,
    required: true,
    default: () => nanoid(7),
    index: { unique: true },
  },
  email: String,
  phone: String,
  city: String,
})

You can also just overwrite _id with nanoid so it doesn't create an extra field in your schema

import { nanoid } from 'nanoid';

const UserSchema = new mongoose.Schema({
  _id: {
    type: String,
    default: () => nanoid(),
  },
  name: string,
  email: String,
  phone: String,
  city: String,
})

Controller

// Saves user to the database
const store = async (req, res, next) => {
  const { name, email, phone, city} = req.body;
  try {
    let user = new User({
      name,
      email,
      phone,
      city,
    });
    const savedUser = await user.save();
    return res.json({
      message: 'User added successfully!',
    });
  } catch (error) {
    console.log(error)
    return res.json({
      message: 'An error occured!',
    });
  }
};

Upvotes: 8

dimamj
dimamj

Reputation: 41

As far as I know, _id (ObjectId) is already unique, and if you want to provide your own _id you just need to set it in the entity.

Upvotes: 4

Buzz Moschetti
Buzz Moschetti

Reputation: 7578

The mongodb javascript driver has UUID already:

db.foo.insert( {x: new UUID()} );
db.foo.aggregate([ {$project: {x:true, x_type: {$type: "$x"}}} ]);
{
    "_id" : ObjectId("61f81af6a565bb368b38e345"),
    "x" : UUID("b639a8b5-2598-429f-92e0-630c6b5bfbdc"),
    "x_type" : "binData"
}

If you don't like the actual UUID object then capture its string rep. Note that unfortunately, toString() on the object does not yield 892ab869-3339-41b3-a612-5c29871f4e57 but rather the whole of UUID("892ab869-3339-41b3-a612-5c29871f4e57") so you have to substr it:

db.foo.insert( {x: (new UUID()).toString().substr(6,36) });
db.foo.aggregate([ {$project: {x:true, x_type: {$type: "$x"}}} ]);
{
    "_id" : ObjectId("61f81b56a565bb368b38e348"),
    "x" : "d5af9fb4-768c-4e17-b69a-8bcd80f8bf1e",
    "x_type" : "string"
}

Or, for simplicity you can use the hex() method:

db.foo.insert( {x: (new UUID()).hex() } );
db.foo.aggregate([ {$project: {x:true, x_type: {$type: "$x"}}} ]);
{
    "_id" : ObjectId("61f81ba9a565bb368b38e34e"),
    "x" : "b9810abea4344932b3da15f7f0d58e2c", // note the dashes went away
    "x_type" : "string"
}

In all cases, the driver -- NOT the server -- will create a unique _id if it is not supplied. Creation of a unique id that is not tied to the database (e.g. _id) can be valuable when integrating and moving data around (compare with moving ROWID out of Oracle in a CSV; not very useful). NOTE: The default generated type for _id is ObjectId which is a type in BSON and is not necessarily tied to MongoDB. That said, UUID is still more of a "machine/DB key" as compared to a familiar business key which can be made unique.

Upvotes: 1

Konflex
Konflex

Reputation: 485

You can't generate unique id technically but it has to be big enough to not generate the same id, example:

function create_UUID(){
    var dt = new Date().getTime();
    var uuid = 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, function(c) {
        var r = (dt + Math.random()*16)%16 | 0;
        dt = Math.floor(dt/16);
        return (c=='x' ? r :(r&0x3|0x8)).toString(16);
    });
    return uuid;
}

Output:

1fe35579-5ce7-46ec-89e0-7e7236700297

Source:

https://www.w3resource.com/javascript-exercises/javascript-math-exercise-23.php

Upvotes: 1

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