connect express to mongodb

1npm i mongoose
2
3const mongoose = require("mongoose");
4
5mongoose
6  .connect(
7    "your mongodb URI",
8    {
9      useNewUrlParser: true,
10      useCreateIndex: true,
11      useFindAndModify: false,
12      useUnifiedTopology: true,
13    }
14  )
15  .then(() => console.log("mongodb connected"))
16  .catch((err) => {
17    console.log(err.message);
18    process.exit(1);
19  });

1//using mongoose
2npm i mongoose
3
4const mongoose = require("mongoose");
5
6mongoose
7  .connect(
8    "your mongodb URI",
9    {
10      useNewUrlParser: true,
11      useCreateIndex: true,
12      useFindAndModify: false,
13      useUnifiedTopology: true,
14    }
15  )
16  .then(() => console.log("mongodb connected"))
17  .catch((err) => {
18    console.err(err.message);
19    process.exit(1);
20  });

1var MongoClient = require('mongodb').MongoClient
2
3MongoClient.connect('mongodb://localhost:27017/animals', function (err, client) {
4  if (err) throw err
5
6  var db = client.db('animals')
7
8  db.collection('mammals').find().toArray(function (err, result) {
9    if (err) throw err
10
11    console.log(result)
12  })
13})
14

1var mysql = require('mysql')
2var connection = mysql.createConnection({
3  host: 'localhost',
4  user: 'dbuser',
5  password: 's3kreee7',
6  database: 'my_db'
7})
8
9connection.connect()
10
11connection.query('SELECT 1 + 1 AS solution', function (err, rows, fields) {
12  if (err) throw err
13
14  console.log('The solution is: ', rows[0].solution)
15})
16
17connection.end()
18