Basic Usages

Redis is a in-memory key-value database. It provides a database which works like a cache. It helps to reduce the loading stress in production. Redis is very fast as the data stored in memory. It always works as a middleware (cache layer) between application and traditional database. Application can just access the cached data which loaded from database previously.

Since it is a cache, data expiration is necessary as memory storage is so expensive. Also, it can be the middleware between process to let them do the data exchange.

It supports following types:

• hashmap

• string

• integer

• float

• list

• set

Note! Json is not officially support, we have to use redis-rejson to support it.

Common Command

Set | Get

redis> SET mykey "Hello"
redis> GET mykey
"Hello"

INCR | DESC

redis> SET mykey "10"
redis> DECR mykey
(integer) 9
redis> INCR mykey
(integer) 10

HSET | HGET

# Structure like this

root = {
	mydata : {
    	name : "nick"
    }	
}

redis> HSET mydata name "nick"
redis> HSET mydata nickname "nicknick"
redis> HGET mydata name
"nick"

SADD | SCARD

redis> SADD myset "nick"
redis> SADD myset "peter"
redis> SADD myset "nick"
redis> SCARD myset
(integer) 2

LPUSH | RPUSH | LSET | LRANGE

redis> LPUSH mylist "a"
redis> LPUSH mylist "b"
redis> RPUSH mylist "c"
redis> LRANGE mylist 0 -1
1) "b"
2) "a"
3) "c"
redis> LSET mylist 0 "d"
redis> LRANGE mylist 0 -1
1) "d"
2) "a"
3) "c"

Reference

• 資料庫的好夥伴：Redis | TechBridge 技術共筆部落格