mongodb connection in express js code example

Example 1: connect mongo to express api

//using mongoose
npm i mongoose

const mongoose = require("mongoose");

mongoose
  .connect(
    "your mongodb URI",
    {
      useNewUrlParser: true,
      useCreateIndex: true,
      useFindAndModify: false,
      useUnifiedTopology: true,
    }
  )
  .then(() => console.log("mongodb connected"))
  .catch((err) => {
    console.err(err.message);
    process.exit(1);
  });

Example 2: how to connect mongodb with node js

async function main(){
    /**
     * Connection URI. Update <username>, <password>, and <your-cluster-url> to reflect your cluster.
     * See https://docs.mongodb.com/ecosystem/drivers/node/ for more details
     */
    const uri = "mongodb+srv://<username>:<password>@<your-cluster-url>/test?retryWrites=true&w=majority";
 

    const client = new MongoClient(uri);
 
    try {
        // Connect to the MongoDB cluster
        await client.connect();
 
        // Make the appropriate DB calls
        await  listDatabases(client);
 
    } catch (e) {
        console.error(e);
    } finally {
        await client.close();
    }
}

main().catch(console.error);

Example 3: how to access a database in express

var mysql = require('mysql')
var connection = mysql.createConnection({
  host: 'localhost',
  user: 'dbuser',
  password: 's3kreee7',
  database: 'my_db'
})

connection.connect()

connection.query('SELECT 1 + 1 AS solution', function (err, rows, fields) {
  if (err) throw err

  console.log('The solution is: ', rows[0].solution)
})

connection.end()