Key design patterns in Redis - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to set a key with a value in Redis.

Redis

SET mykey [1]

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

AGET

Bvalue123

CDEL

DEXPIRE

Attempts:

3 left

💡 Hint

Common Mistakes

Using a command like GET or DEL instead of a value.

Leaving the value blank.

The SET command stores the given value under the specified key.

2fill in blank

medium

Complete the code to retrieve the value of a key in Redis.

Redis

[1] mykey

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

AGET

BSET

CDEL

DEXPIRE

Attempts:

3 left

💡 Hint

Common Mistakes

Using SET instead of GET.

Using DEL which deletes the key.

The GET command fetches the value stored at the given key.

3fill in blank

hard

Fix the error in the code to delete a key in Redis.

Redis

[1] mykey

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

AGET

BSET

CEXPIRE

DDEL

Attempts:

3 left

💡 Hint

Common Mistakes

Using GET or SET which do not delete keys.

Using EXPIRE which only sets a timeout.

The DEL command removes the key and its value from Redis.

4fill in blank

hard

Fill both blanks to set a key with an expiration time of 60 seconds.

Redis

SET [1] [2] EX 60

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

Amykey

Bvalue123

Cvalue456

Dmyvalue

Attempts:

3 left

💡 Hint

Common Mistakes

Swapping key and value positions.

Using a wrong value or key name.

First, specify the key name, then the value to store. The EX 60 sets the key to expire after 60 seconds.

5fill in blank

hard

Fill all three blanks to increment a counter key by 1 and get its new value.

Redis

[1] [2]
[3] [2]

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

AINCR

Bcounter

DGET

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong commands or missing the key name.

Trying to increment a non-integer key.

The INCR command increases the integer value of the key by 1. Then GET retrieves the updated value.

Practice

1. What is the main purpose of using key design patterns in Redis?

easy

A. To delete all keys automatically

B. To organize data for easy access and management

C. To slow down data retrieval

D. To increase the size of the database

Solution

1. Step 1: Understand Redis key design patterns

   Key design patterns help organize Redis keys logically.

2. Step 2: Identify the main benefit

   Organizing keys makes data easier to access and manage efficiently.

3. Final Answer:

   To organize data for easy access and management -> Option B

4. Quick Check:

   Key design patterns = organize data [OK]

Hint: Think about why organization helps in real life [OK]

Common Mistakes:

• Confusing organization with database size
• Assuming patterns slow down Redis
• Thinking patterns delete keys automatically

2. Which of the following is a correct Redis key pattern to group user data by user ID?

easy

A. user:1234:name

B. user-1234-name

C. user1234name

D. user/1234/name

Solution

1. Step 1: Identify common Redis key pattern syntax

   Redis keys often use colons ':' as separators for readability and grouping.

2. Step 2: Compare options

   user:1234:name uses colons to separate user, ID, and attribute clearly.

3. Final Answer:

   user:1234:name -> Option A

4. Quick Check:

   Colon separators = correct pattern [OK]

Hint: Use colons to separate parts of keys [OK]

Common Mistakes:

• Using dashes or slashes which are less common
• Not separating parts clearly
• Combining all parts without separators

3. Given these Redis keys: order:1001:status, order:1002:status, and order:1001:items, which command retrieves the status of order 1002?

medium

A. GET order:1001:items

B. GET order:1002:items

C. GET order:1002:status

D. GET order:1001:status

Solution

1. Step 1: Identify the key for order 1002 status

   The key format is order:<order_id>:status, so for 1002 it is order:1002:status.

2. Step 2: Match the command to the key

   GET order:1002:status retrieves the status of order 1002.

3. Final Answer:

   GET order:1002:status -> Option C

4. Quick Check:

   Correct key = order:1002:status [OK]

Hint: Match key parts exactly to get correct data [OK]

Common Mistakes:

• Mixing order IDs in keys
• Using wrong attribute like items instead of status
• Confusing similar keys

4. You have keys like session-123 and session:124. Why might this inconsistency cause problems?

medium

A. Redis will merge both keys automatically

B. Redis will throw a syntax error

C. Keys with dashes are not allowed in Redis

D. It breaks pattern consistency, making data harder to manage

Solution

1. Step 1: Understand key pattern consistency

   Consistent key patterns help group and find related data easily.

2. Step 2: Analyze the impact of mixed separators

   Using both dashes and colons breaks this consistency, causing confusion.

3. Final Answer:

   It breaks pattern consistency, making data harder to manage -> Option D

4. Quick Check:

   Inconsistent keys = management issues [OK]

Hint: Always use one separator style consistently [OK]

Common Mistakes:

• Thinking Redis forbids dashes
• Expecting syntax errors from mixed separators
• Assuming Redis merges keys automatically

5. You want to store product reviews in Redis for multiple products and users. Which key design pattern is best to efficiently group reviews by product and user?

hard

A. review:<product_id>:<user_id>

B. <product_id>-review-<user_id>

C. review<product_id><user_id>

D. review/<product_id>/<user_id>

Solution

1. Step 1: Identify clear, scalable key pattern

   Using colons to separate product and user IDs groups reviews logically.

2. Step 2: Evaluate options for clarity and consistency

   review:<product_id>:<user_id> uses colons and a prefix 'review' for easy filtering and management.

3. Final Answer:

   review:<product_id>:<user_id> -> Option A

4. Quick Check:

   Colon-separated keys = best practice [OK]

Hint: Use prefixes and colons to group related data [OK]

Common Mistakes:

• Using ambiguous separators like dashes or slashes
• Combining parts without separators
• Not using a clear prefix for grouping