Redis

Advantages

• Faster relational database (data is read and modified from RAM rather than main memory disk)
• Every piece of data uses key value pair
• Can act as a cache [middle layer] between database

Applications

Real Time Analytics, Chatting, Social Media, Live leaderboards, Geopositioning

Commands

• lsof -i tcp:6379
• kill -9
• brew services stop redis
• docker run -d -p 6379:6379 --name myredis redis

Strings

• SET key value: Set the value of a key
• GET key: Get the value of a key
• DEL key [key ...]: Delete one or more keys
• INCR key: Increment the integer value of a key
• DECR key: Decrement the integer value of a key
• APPEND key value: Append a value to a key

Hashes

• HSET key field value: Set the value of a field in a hash
• HGET key field: Get the value of a field in a hash
• HGETALL key: Get all the fields and values in a hash
• HDEL key field [field ...]: Delete one or more fields from a hash
• HKEYS key: Get all the fields in a hash
• HVALS key: Get all the values in a hash

Lists

• LPUSH key value [value ...]: Insert one or more values at the beginning of a list
• RPUSH key value [value ...]: Insert one or more values at the end of a list
• LPOP key: Remove and return the first element of a list
• RPOP key: Remove and return the last element of a list
• LRANGE key start stop: Get a range of elements from a list by their index

Sets

• SADD key member [member ...]: Add one or more members to a set
• SMEMBERS key: Get all the members of a set
• SISMEMBER key member: Check if a member exists in a set
• SREM key member [member ...]: Remove one or more members from a set
• SCARD key: Get the number of members in a set

Sorted Sets

• ZADD key score member [score member ...]
• ZRANGE key start stop [WITHSCORES]: Get a range of members from a sorted set by their rank, optionally with their scores
• ZREVRANGE key start stop [WITHSCORES]: Get a range of members from a sorted set by their rank, in reverse order, optionally with their scores
• ZCARD key: Get the number of members in a sorted set
• ZSCORE key member: Get the score of a member in a sorted set
• ZREM key member [member ...]: Remove one or more members from a sorted set

Transactions

• MULTI
• [list of commands]
• EXEC