Denormalization for speed in Redis - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to set a user's name in Redis.

Redis

redis.call('SET', 'user:[1]:name', 'Alice')

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

Aname

B123

Cuser

Dprofile

Attempts:

3 left

💡 Hint

Common Mistakes

Using generic words like 'user' or 'name' without an ID causes key collisions.

The key should include the user ID to uniquely identify the user's name.

2fill in blank

medium

Complete the code to retrieve the user's email from Redis.

Redis

local email = redis.call('GET', 'user:[1]:email')

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

Auser

Bprofile

Cemail

D456

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'email' or 'user' as the ID part of the key instead of the actual user ID.

The key must include the user ID to get the correct email.

3fill in blank

hard

Fix the error in the code to increment the user's login count.

Redis

redis.call('[1]', 'user:789:login_count')

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

AINCR

BSET

CGET

DDEL

Attempts:

3 left

💡 Hint

Common Mistakes

Using SET replaces the value instead of incrementing it.

Using GET only reads the value without changing it.

INCR increases the integer value stored at the key by one, perfect for counting logins.

4fill in blank

hard

Fill both blanks to store a user's profile with denormalized data.

Redis

redis.call('[1]', 'user:[2]', 'name', 'Bob', 'email', '[e-mail]')

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

AHMSET

BSET

C101

Duser

Attempts:

3 left

💡 Hint

Common Mistakes

Using SET only stores a single string, not multiple fields.

Using a generic key like 'user' without an ID causes data overwrite.

HMSET sets multiple fields in a hash, and the key includes the user ID 101.

5fill in blank

hard

Fill all three blanks to create a denormalized Redis key for fast access.

Redis

redis.call('[1]', 'order:[2]:[3]', 'status', 'shipped')

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

AHMSET

B789

Cuser123

DSET

Attempts:

3 left

💡 Hint

Common Mistakes

Using SET stores only a string, not multiple fields.

Missing user ID in the key reduces denormalization benefits.

HMSET stores multiple fields, the order ID is 789, and user123 identifies the user for denormalization.