How to update a record in your local/custom database in Node.js?
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.
There are some steps involve in creating the local database and create, find, update information of it. These steps are as follows:
- Create package.json file in root of project directory using the following command:
npm init -y
- Install express and body-parser package using the following command:
npm install express npm install body-parser
- Create a POST route to request for particular user database using id.
- 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 update a record from database using id.
Example: This example illustrates how to update a record in a local custom database.
Filename: index.js
const express = require( 'express' ) const bodyParser = require( 'body-parser' ) const repo = require( './repository' ) const updateTemplet = require( './updateRecordForm' ) const app = express() const port = process.env.PORT || 3000 // The body-parser middleware to parse form data app.use(bodyParser.urlencoded({extended : true })) // Home page app.get( '/' , (req, res) => { const id = '32b3a9f5d8f33a8d' res.send(` <form method= 'GET' action= './update/${id}' > <button>Update Record</button> </form> `) }) // Get route to show update form app.get( '/update/:id' , async (req, res) => { const id = req.params.id const temp = await (updateTemplet({id})) res.send(temp) }) // Post route to update record app.post( '/update/:id' , async (req, res) => { const id = req.params.id const record = await repo.update(id, req.body) console.log(`Record Updated : \n${JSON.stringify(record, null , 2)}`) res.send( 'Record Updated' ) }) // Server setup app.listen(port, () => { console.log(`Server start on port ${port}`) }) |
Filename: repository.js This file contains all the logic to update a record of custom database.
// Importing node.js file system, crypto module const fs = require( 'fs' ) class Repository { constructor(filename) { // The filename where datas are // going to store if (!filename) { throw new Error( 'Filename is required' + ' to create a datastore!' ) } this .filename = filename try { fs.accessSync( this .filename) } catch (err) { // If file not exist it is created // with empty array fs.writeFileSync( this .filename, '[]' ) } } // The findById method used in the example async findById(id) { // Read all filecontents of the datastore const jsonRecords = await fs.promises.readFile( this .filename, { encoding: 'utf8' }) // Parsing JSON records in javascript // object type records const objRecord = JSON.parse(jsonRecords) // Search for required record const requiredRecord = objRecord .find(record => record.id === id) return requiredRecord } // Update Method async update(id, attrs) { // Read all file contents of the datastore const jsonRecords = await fs.promises.readFile( this .filename, { encoding: 'utf8' }) // Parsing json records in javascript // object type records const records = JSON.parse(jsonRecords) // Find target record to update with id const record = records.find( eachRecord => eachRecord.id === id) // If given id not belongs to any // record in database if (!record) { throw new Error(`Id '${id}' not found`) } // Update record Object.assign(record, attrs) // Write all records back to the // custom database await fs.promises.writeFile( this .filename, JSON.stringify(records, null , 2) ) return record } } // The 'datastore.json' file created at // runtime if it not exist, here we try // to update information of database // that means database(datastore.json) // already exist and there are also // records in it. module.exports = new Repository( 'datastore.json' ) |
Filename: updateRecordForm.js
const repo = require( './repository' ) module.exports = async ({ id }) => { const record = await repo.findById(id) return ` <div> <form method= 'POST' > <div> <div> <label id= 'email' >Username</label> </div> <input type= 'text' name= 'email' value=${record.email} for = 'email' > </div> <div> <div> <label id= 'password' >Password</label> </div> <input type= 'password' name= 'password' value=${record.password} for = 'password' > </div> <div> <div> <label id= 'name' >Name</label> </div> <input type= 'text' name= 'name' value=${record.name} for = 'name' > </div> <button>Update</button> </div> </form> </div> ` } |
Filename: package.json
Run index.js file using the following command:
node index.js
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. But here we try to update a record in the database that means program suppose to have already run once and some records are added into the database that we try to update.