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Redis hashes are used to store structured data under a single key.

A hash is essentially a collection of field–value pairs, similar to an object or dictionary.

Example structure:

user:1001
   name → "Ufraan"
   age → "20"
   city → "Hyderabad"

Instead of creating separate keys for each attribute, hashes group related fields together.

Hashes are commonly used for:

• user profiles
• configuration data
• application objects

Setting Fields

HSET

Adds or updates a field inside a hash.

HSET user:1001 name "ufraan"
HSET user:1001 age 20
HSET user:1001 city "Hyderabad"

Retrieving Data

HGET

Retrieve a specific field.

HGET user:1001 name

Output:

"ufraan"

HGETALL

Returns all fields and values.

HGETALL user:1001

Example output:

1) "name"
2) "ufraan"
3) "age"
4) "20"
5) "city"
6) "Hyderabad"

Updating Fields

Running HSET again updates the value.

HSET user:1001 age 21

Removing Fields

HDEL

Deletes a field from the hash.

HDEL user:1001 city

Getting All Field Names

HKEYS

HKEYS user:1001

Returns:

"name"
"age"

Why Hashes Are Useful

Hashes allow storing related information in one place instead of spreading data across many keys.

For example, instead of:

user:1001:name
user:1001:age
user:1001:city

You can simply store:

user:1001 → { name, age, city }

This keeps Redis data more organized and efficient.

Related: [[Redis]] [[Redis - Lists]] [[Redis - Sets]] [[Redis - Strings]] [[Redis - Sorted sets]]