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How to add unique Id to each record in your local/custom database in Node.js ?

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The custom database signifies the local database in your file system. There are two types of database ‘SQL’ and ‘NoSQL’. In SQL database data are stored as table manner and in Nosql database data are stored independently with some particular way to identify each record independently. We can also create our own database or datastore locally in Nosql manner. To store the information in a NoSQL manner, we have to add a unique Id to each record so that each record can be identified independently. There are some steps involve in creating the local database and add records with unique Id to it. These steps are as follows:
  • Create package.json file in root of project directory. Command to create package.json file
    npm init -y
  • Install express and body-parser package. Command to install packages
    npm install express body-parser
  • Create a GET route to show the form (HTML form to submit the information to the database).
  • Create the subsequent post route to handle the form submission request.
  • Set the server to run on a specific port(Developer’s port – 3000).
  • Create a repository file and add all the logic related to creating local database.
  • Create a method in repository file to add a unique alphanumeric id to each record.
  • Create a method in repository file to add each unique record into the database in json format.
This example illustrates how to create a local database and add records to it with a unique id. Filename: index.js
const express = require('express')
const bodyParser = require('body-parser')
const repo = require('./repository')
const app = express()
const port = process.env.PORT || 3000
// The body-parser middleware 
// to parse form data
app.use(bodyParser.urlencoded({extended : true}))
// Get route to display HTML form
app.get('/signup', (req, res) => {
     <form method='POST'>
           <label id='email'>Username</label>
         <input type='text' name='email' 
           <label id='password'>Password</label>
         <input type='password' name='password'
         <button>Sign Up</button>
// Post route to handle form submission
// logic and add data to the database'/signup', async (req, res) => {
  const {email, password} = req.body
  const addedRecord = await 
    repo.createNewRecord({email, password})
  console.log(`Added Record : 
    ${JSON.stringify(addedRecord, null, 4)}`)
  res.send("Information added to the "
        + "database successfully.")
// Server setup
app.listen(port, () => {
  console.log(`Server start on port ${port}`)

Filename: repository.js
// Importing node.js file system, crypto module 
const fs = require('fs')
const crypto = require('crypto')
class Repository {
  constructor(filename) {
    // Filename where datas are going to store
    if(!filename) {
      throw new Error(
'Filename is required to create a datastore!')
    this.filename = filename
    try {
    } catch (err) {
      // If file not exist
      // it is created with empty array
      fs.writeFileSync(this.filename, '[]')
  // Logic to add data or record
  async createNewRecord(attributes) {
    // Assign unique Id to each record = this.generateUniqueID()
    // Read filecontents of the datastore
    const jsonRecords = await 
      fs.promises.readFile(this.filename, {
      encoding : 'utf8'
    // Parsing JSON records in JavaScript
    // object type records
    const objRecord = JSON.parse(jsonRecords)
    // Adding new record
    // Writing all records back to the file
    await fs.promises.writeFile(
      JSON.stringify(objRecord, null, 2)   
    return attributes;
  // Method to generate unique ID 
  generateUniqueID() {
    return crypto.randomBytes(8).toString('hex')
// The 'datastore.json' file created at runtime 
// and all the information provided via signup
// form store in this file in JSON format.
module.exports = new Repository('datastore.json')

Package.json file: Step to run this program Run index.js file using the following command:
node index.js
Form to submit the responses: Note: Here three responses are submitted one after other and all the responses are stored in datastore.json file. Redirected page after submitting the request: Output: Database: Note: For the first time running the program database(datastore.json) file not exist in the project directory, it created dynamically after running the program and store the submitted response. After that, all the submitted responses are appended in the database one by one.

Last Updated : 18 Jul, 2020
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