Raw queries when needed in Express - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to execute a raw SQL query using Express with a database client.

Express

db.query([1], (err, result) => {
  if (err) throw err;
  res.send(result.rows);
});

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

Adb.execute('SELECT * FROM users')

BSELECT * FROM users

C"SELECT * FROM users"

Dquery('SELECT * FROM users')

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting to put the SQL query inside quotes.

Using incorrect method names like execute or query without context.

The raw SQL query must be a string passed to the query method. Option C correctly provides the SQL string.

2fill in blank

medium

Complete the code to safely insert a user name using parameterized raw query to avoid SQL injection.

Express

const sql = 'INSERT INTO users(name) VALUES($1)';
db.query(sql, [[1]], (err, res) => {
  if (err) throw err;
  console.log('User added');
});

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

AuserName

Busername

Cname

Dreq.body.name

Attempts:

3 left

💡 Hint

Common Mistakes

Passing variable names that are undefined in the context.

Not using parameterized queries and inserting values directly.

The user name comes from the request body, so req.body.name is the correct value to pass as parameter.

3fill in blank

hard

Fix the error in the raw query callback by completing the missing parameter to handle the result.

Express

db.query('SELECT * FROM products', (err, [1]) => {
  if (err) {
    console.error(err);
    return;
  }
  res.json([1].rows);
});

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

Aresult

Bresponse

Cdata

Doutput

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect parameter names that do not match the result object.

Forgetting to use the result parameter to access rows.

The second parameter in the callback is commonly named result and contains the query result including rows.

4fill in blank

hard

Fill both blanks to create a raw query that updates a user's email by id using parameters.

Express

const sql = 'UPDATE users SET email = $1 WHERE id = $2';
db.query(sql, [[1], [2]], (err, res) => {
  if (err) throw err;
  res.send('Email updated');
});

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

Areq.body.email

Breq.params.id

CuserEmail

DuserId

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up the order of parameters.

Using undefined variables instead of request data.

The email comes from req.body.email and the user id from req.params.id to safely update the record.

5fill in blank

hard

Fill all three blanks to write a raw query that deletes a user by id and logs the affected row count.

Express

const sql = 'DELETE FROM users WHERE id = $1';
db.query(sql, [[1]], (err, [2]) => {
  if (err) throw err;
  console.log('Deleted rows:', [3].rowCount);
});

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

Areq.params.userId

Bresult

Cres

Dreq.body.id

Attempts:

3 left

💡 Hint

Common Mistakes

Using request body instead of URL params for id.

Not using the correct result parameter to get rowCount.

The id to delete is from req.params.userId, the callback result parameter is named result, and result.rowCount gives the number of deleted rows.