Redis - Hashes


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Redis Hashes are maps between the string fields and the string values. Hence, they are the perfect data type to represent objects.

In Redis, every hash can store up to more than 4 billion field-value pairs.

Example

redis 127.0.0.1:6379> HMSET tutorialspoint name "redis tutorial" 
description "redis basic commands for caching" likes 20 visitors 23000 
OK 
redis 127.0.0.1:6379> HGETALL tutorialspoint  
1) "name" 
2) "redis tutorial" 
3) "description" 
4) "redis basic commands for caching" 
5) "likes" 
6) "20" 
7) "visitors" 
8) "23000"

In the above example, we have set Redis tutorials detail (name, description, likes, visitors) in hash named ‘tutorialspoint’.

Redis Hash Commands

Following table lists some basic commands related to hash.

S.No Command & Description
1 HDEL key field2 [field2]

Deletes one or more hash fields.

2 HEXISTS key field

Determines whether a hash field exists or not.

3 HGET key field

Gets the value of a hash field stored at the specified key.

4 HGETALL key

Gets all the fields and values stored in a hash at the specified key

5 HINCRBY key field increment

Increments the integer value of a hash field by the given number

6 HINCRBYFLOAT key field increment

Increments the float value of a hash field by the given amount

7 HKEYS key

Gets all the fields in a hash

8 HLEN key

Gets the number of fields in a hash

9 HMGET key field1 [field2]

Gets the values of all the given hash fields

10 HMSET key field1 value1 [field2 value2 ]

Sets multiple hash fields to multiple values

11 HSET key field value

Sets the string value of a hash field

12 HSETNX key field value

Sets the value of a hash field, only if the field does not exist

13 HVALS key

Gets all the values in a hash



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