Redis Data type: Hashes

Redis Hash is a string-type field and value mapping table.

It's add, delete operations are O (1) (average), hash is particularly suitable for storing objects

Storing an object in a hash type always consumes less memory and makes it easier to access

The entire object.

Hset method: Sets the hash field to the specified value, and if key does not exist, first create

127.0.0.1:6379> hset user:001 Name Xiaoming
(integer) 1
127.0.0.1:6379> hget user:001 Name
"Xiaoming"

Hsetnx method: Sets the hash field to the specified value, and if key does not exist, it is created first.

Returns 0 if present.

127.0.0.1:6379> hsetnx user:001 name Xiaohong
(integer) 0

Hmset method: Batch Set hash field

127.0.01:6379> Get user:002 Name
(Error) ERR wrong number of arguments for ' get ' command
127.0.01:6379> hget user:002 Name
"Xiaoming"
127.0.01:6379> Hget user:002 Age
"10"
127.0.01:6379> Hget user:002 Gender
"1"

Hget method: Gets the value of the filed specified by the hash

Hmget method: Bulk Get hash specified filed value

127.0.01:6379> hmget user:002 Name Age gender
1) "Xiaoming"
2) "10"
3) "1"

Hincrby method: Specifies the hash field plus the specified value

127.0.01:6379> Hincrby user:002 age 8
(integer) 18
127.0.01:6379> hmget user:002 Name Age gender
1) "Xiaoming"
2) "18"
3) "1"

Hexists method: Test whether the specified field exists, existence returned 1

127.0.01:6379> hexists user:002 Name
(integer) 1

Hlen method: Returns the number of keys for the specified hash

127.0.01:6379> Hlen user:002
(integer) 3

Hdel method: Delete the filed of the specified hash

127.0.01:6379> Hdel user:002 Age
(integer) 1
127.0.01:6379> Hget user:002 Age
(nil)

Hkeys method: Returns all field of hash

127.0.01:6379> Hkeys user:002
1) "Name"
2) "Gender"

Hvals method: Returns all the value of a hash

127.0.01:6379> hvals user:002
1) "Xiaoming"
2) "1"

Hgetall method: Returns all fields and their corresponding values

127.0.01:6379> Hgetall user:002
1) "Name"
2) "Xiaoming"
3) "Gender"
4) "1"

Redis Data type: Hashes