HMSET and HMGET for bulk in Redis - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the Redis command HMSET do?

HMSET sets multiple fields and their values in a hash stored at a key in Redis. It allows you to add or update many fields at once.

beginner

How do you retrieve multiple fields from a Redis hash at once?

You use the HMGET command, which gets the values of specified fields from a hash key in one call.

beginner

Example: What does HMSET user:1 name "Alice" age "30" city "NY" do?

It creates or updates the hash at key user:1 with fields name, age, and city set to "Alice", "30", and "NY" respectively.

beginner

What will HMGET user:1 name city return if the hash contains those fields?

It returns an array of values for the fields name and city, for example: ["Alice", "NY"].

intermediate

Why use HMSET and HMGET instead of multiple HSET or HGET calls?

Because HMSET and HMGET reduce the number of commands sent to Redis, making operations faster and more efficient when working with many fields.

What does the Redis command HMSET do?

A Gets multiple fields from a hash

B Creates a new database

C Deletes a hash key

D Sets multiple fields in a hash at once

HMSET sets multiple fields and values in a Redis hash key.

Which command retrieves multiple fields from a Redis hash in one call?

A HMGET

B HDEL

C HGETALL

D HSET

HMGET fetches specified fields from a hash key.

If you want to set fields name and age in a hash key user:2, which command is correct?

A HGET user:2 name

B HMGET user:2 name age

C HMSET user:2 name "Bob" age "25"

D DEL user:2

HMSET sets multiple fields in a hash key.

What does HMGET user:1 name city return if user:1 has those fields?

A A single string with both values

B An array of values for <code>name</code> and <code>city</code>

C Deletes the fields

D An error

HMGET returns an array of values for requested fields.

Why is using HMSET and HMGET better than multiple HSET or HGET calls?

A They reduce network calls and improve performance

B They create new databases

C They delete the hash

D They are slower

Using bulk commands reduces the number of calls to Redis, improving speed.

Explain how HMSET and HMGET work together to manage multiple fields in a Redis hash.

Think about setting and getting many fields at once.

Describe a real-life example where using HMSET and HMGET would be helpful.

Imagine a user profile with name, age, city, and more.