Why database connectivity matters in Node.js - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to import the database client module.

Node.js

const dbClient = require('[1]');

Drag options to blanks, or click blank then click option'

Aexpress

Bmongodb

Cfs

Dhttp

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'express' or 'http' which are for servers, not databases.

The mongodb module is used to connect to a MongoDB database in Node.js.

2fill in blank

medium

Complete the code to connect to the database using the client.

Node.js

dbClient.connect('[1]', (err) => {
  if (err) throw err;
  console.log('Connected!');
});

Drag options to blanks, or click blank then click option'

Amongodb://localhost:27017

Bhttp://localhost:3000

Cftp://localhost

Dfile://localhost

Attempts:

3 left

💡 Hint

Common Mistakes

Using HTTP or FTP protocols which are not for database connections.

The connection string for MongoDB starts with mongodb:// followed by the host and port.

3fill in blank

hard

Fix the error in the code to properly close the database connection.

Node.js

dbClient.[1]();

Drag options to blanks, or click blank then click option'

Astop

Bdisconnect

Cend

Dclose

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'disconnect' or 'end' which are not valid methods for MongoDB client.

The correct method to close a MongoDB client connection is close().

4fill in blank

hard

Fill both blanks to create a query that finds all users older than 18.

Node.js

db.collection('users').find({ age: { [1]: [2] } }).toArray((err, results) => {
  if (err) throw err;
  console.log(results);
});

Drag options to blanks, or click blank then click option'

A$gt

B18

C$lt

D21

Attempts:

3 left

💡 Hint

Common Mistakes

Using '$lt' which means 'less than', or wrong age values.

The MongoDB query operator $gt means 'greater than'. We want users older than 18.

5fill in blank

hard

Fill all three blanks to insert a new user with name and age into the database.

Node.js

db.collection('[1]').insertOne({ name: '[2]', age: [3] }, (err, res) => {
  if (err) throw err;
  console.log('User added');
});

Drag options to blanks, or click blank then click option'

Ausers

BAlice

C30

Dproducts

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong collection names or putting age as a string.

We insert into the 'users' collection a user named 'Alice' who is 30 years old.