What is the difference between HSET and HMSET method in redis database

Question

In my application im using redis database.I have gone through their documentation but i couldn\'t find the difference between HSET and HMSET.

Answer 1

HSET key field value:

Sets field in the hash stored at key to value. If key does not exist, a new key holding a hash is created. If field already exists in the hash, it is overwritten.

HMSET key field value [field value ...]

Sets the specified fields to their respective values in the hash stored at key. This command overwrites any existing fields in the hash. If key does not exist, a new key holding a hash is created.

For more redis commands information, click here.

Answer 2

The only difference between the commands HSET and HMSET is the return value of the commands.

HSET return value (Integer reply):

• # if the field is a new field in the hash and value was set. (where # is the number of new fields created )
• 0 if the field already exists in the hash and the value was updated.

HMSET returns a simple string as a reply.

Answer 3

HSET used to be able to set only one key-value pair. And if you needed to set several at once, you would have to use HMSET (M for multi). That was changed a few years ago, to allow both commands to accept multiple pairs. And now HMSET is redundant.

From official documentation:

As per Redis 4.0.0, HMSET is considered deprecated. Please use HSET in new code.