====== redis ======

  * [[https://medium.com/@stockholmux/from-sql-to-redis-chapter-1-145c82e4baa0|from sql to redis]]
  * [[https://joshtronic.com/2013/07/29/mysql-and-redis-command-equivalents/|from mysql to redis]]

===== string =====


type **string**: store a value [integer, string, ...] belong a key [string]
<code>
SET connections 10
INCR connections => 11
INCR connections => 12
DEL connections
INCR connections => 1
</code>

expiring key
<code>
SET resource:lock "Redis Demo"
EXPIRE resource:lock 120
</code>

===== list =====

A list have an order

RPUSH puts the new value at the end of the list. LPUSH puts the new value at the start of the list. LLEN, LPOP, RPOP
<code>
RPUSH friends "Alice"
RPUSH friends "Bob"
</code>

<code>
LRANGE friends 0 -1 => 1) "Sam", 2) "Alice", 3) "Bob"
LRANGE friends 0 1 => 1) "Sam", 2) "Alice"
LRANGE friends 1 2 => 1) "Alice", 2) "Bob"
</code>

===== set =====

A set does not have an order but each element may only appear once. 

<code>
SADD superpowers "flight"
SADD superpowers "x-ray vision"
SADD superpowers "reflexes"
SREM superpowers "reflexes"

SISMEMBER superpowers "flight" => 1
SISMEMBER superpowers "reflexes" => 1
</code>

===== sorted set =====

A sorted set is similar to a regular set, but now each value has an associated score. This score is used to sort the elements in the set.
<code>
ZADD hackers 1940 "Alan Kay"
ZADD hackers 1969 "Linus Torvalds"
ZADD hackers 1906 "Grace Hopper"
ZADD hackers 1953 "Richard Stallman"

ZRANGE hackers 2 4
1) "Richard Stallman"
2) "Linus Torvalds"
</code>


===== hash =====


type **hash** for **tables and rows**

namespace:table:id
<code>
INCR gianoauth:realm:next_user_id => 1
HSET gianoauth:realm:user:1 id 1 username "scipio" name "Stefano Scipioni" password "hash" visits 0
</code>

add an INDEX with **sets**: collections of strings that are unordered and cannot contain duplicates
<code>
SADD gianoauth:realm:all-users gianoauth:realms:users:1
</code>

visits
<code>
HINCRBY gianoauth:realm:user:1 visits 1 => 2
</code>

use multi exec to surround HSET and SADD
<code>
MULTI
HSET ...
HSET ...
SADD ...
EXEC
</code>

**sorted set**: like a set a sorted set only allows members without repeats, but also allows you to specify a score

<code>
ZADD gianoauth:realms:priceIndex 10.99 scipio
</code>
===== gui =====

  * [[http://fastoredis.com|fastoredis]]

===== server =====

<code>
sudo apt install -y redis-server redis-tools
</code>