Why SQL integration matters in Express - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to import the SQL library in an Express app.

Express

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

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

Amysql

Bfs

Chttp

Dexpress

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'express' instead of the SQL library name.

Using 'http' or 'fs' which are unrelated to SQL.

The mysql package is used to connect SQL databases with Express apps.

2fill in blank

medium

Complete the code to create a connection to the SQL database.

Express

const connection = sql.createConnection({ host: 'localhost', user: 'root', password: '[1]', database: 'testdb' });

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

A1234

Bpassword123

Cexpress

Droot

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'root' as password instead of the actual password.

Using 'express' which is unrelated.

The password field should be the actual password string for the database user.

3fill in blank

hard

Fix the error in the query execution code by completing the blank.

Express

connection.query('SELECT * FROM users', function(err, results) { if (err) throw [1]; console.log(results); });

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

Aerror

Bexception

Cerr

Dresults

Attempts:

3 left

💡 Hint

Common Mistakes

Throwing 'error' which is undefined here.

Throwing 'results' which is the data, not the error.

The error object passed to the callback is named err, so we throw err to handle errors properly.

4fill in blank

hard

Fill both blanks to create a simple Express route that queries the database and sends results.

Express

app.get('/users', (req, res) => { connection.query('[1]', (err, results) => { if (err) return res.status(500).send(err); res.[2](results); }); });

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ASELECT * FROM users

Bsend

Cjson

DSELECT * FROM products

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong table name in the query.

Using res.send() which sends raw data, not JSON.

The SQL query should select all users. The response should send JSON data to the client.

5fill in blank

hard

Fill all three blanks to handle a POST request that inserts a new user into the database.

Express

app.post('/add-user', (req, res) => { const { name, email } = req.body; const query = 'INSERT INTO users (name, email) VALUES (?, ?)'; connection.query(query, [[1], [2]], (err, results) => { if (err) return res.status(500).send(err); res.[3]({ message: 'User added', id: results.insertId }); }); });

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

Aname

Bemail

Cjson

Dres.send

Attempts:

3 left

💡 Hint

Common Mistakes

Passing wrong variables to the query parameters.

Using res.send instead of res.json.

We pass name and email from the request body as parameters to the query. Then respond with JSON to confirm success.