Redis

DS2

https://redis.io/docs/latest/develop/data-types/

String (base) value

• GET, SET, DEL

Hash set

• HGET
• HSET
• HKEYS hashmap(list of keys)
• HVALS hasHmap(list of values)
• HDEL hashmap key - delete value by key
• HLEN hashmap - length of HMAP

Sorted set

https://redis.io/docs/latest/develop/data-types/sorted-sets/ 0 and -1 means from element index 0 to the last element (-1 works here just as it does in the case of the LRANGE command).