redis基礎命令之key基本操作命令
redis是key-value儲存的，放在記憶體中，並在磁碟持久化的資料結構儲存系統，它可以用作資料庫、快取和訊息中介軟體。
通過set key value來儲存，通過get key來獲取值
一．建立key----set/setnx/mset/msetnx
1.建立單個key
set key value：設定key的值，若存在則覆蓋
setnx key value：設定key的值，若存在則不操作
192.168.10.12:6379> set gw1 10
OK
192.168.10.12:6379> get gw1
"10"
192.168.10.12:6379> keys *
1) "gw1"
192.168.10.12:6379> set gw2 20
OK
192.168.10.12:6379> get gw2
"20"
192.168.10.12:6379> keys *
1) "gw1"
2) "gw2"
192.168.10.12:6379> setnx gw4 40
(integer) 1
192.168.10.12:6379> get gw4
"40"
192.168.10.12:6379> setnx gw4 50
(integer) 0
192.168.10.12:6379> get gw4
"40"
2.建立多個key
MSET key1 value1 key2 value2 ... keyN valueN ：設定這些key的值，若存在則覆蓋
MSETNX key1 value1 key2 value2 ... keyN valueN：同mset，但如果其中一個key已經存在了，則都不設定。這些操作都是原子的
192.168.10.12:6379> mset g1 a g2 b g3 c
OK
192.168.10.12:6379> keys *
4) "g2"
7) "g1"
8) "g3"
192.168.10.12:6379> mset g3 d g4 f g5 g
OK
192.168.10.12:6379> keys *
5) "g4"
9) "g3"
11) "g5"
192.168.10.12:6379> get g3
"d"
192.168.10.12:6379> get g4
"f"
192.168.10.12:6379> get g5
"g"
192.168.10.12:6379> msetnx g5 h g6 i g7k
(integer) 0
192.168.10.12:6379> keys *
5) "g4"
9) "g3"
11) "g5"
192.168.10.12:6379> get g5
"g"
192.168.10.12:6379> get g6
(nil)
二．檢視key
1.檢視所有key----keys *
keys *
keys "*"
2.根據key檢視value----getkey
192.168.10.12:6379> set gw1 10
OK
192.168.10.12:6379> get gw1
"10"
192.168.10.12:6379> keys *
1) "gw1"
192.168.10.12:6379> set gw2 20
OK
192.168.10.12:6379> get gw2
"20"
192.168.10.12:6379> keys *
1) "gw1"
2) "gw2"
3.檢視匹配字首或字尾的key----keys *substr*
192.168.10.12:6379> keys *
1) "gw1"
2) "gw2"
3) "gao2"
4) "gao1"
192.168.10.12:6379> keys gw*
1) "gw1"
2) "gw2"
192.168.10.12:6379> keys gao*
1) "gao2"
2) "gao1"
192.168.10.12:6379> keys *g*
1) "gw1"
2) "gw2"
3) "gao2"
4) "gao1"
192.168.10.12:6379> keys *1
1) "gw1"
2) "gao1"
4.隨機取出一個key----randomkey
192.168.10.12:6379> randomkey
"gao2"
192.168.10.12:6379> randomkey
"gao2"
192.168.10.12:6379> randomkey
"gw2"
192.168.10.12:6379> randomkey
"gw2"
192.168.10.12:6379> randomkey
"gao2"
5.檢視key的型別----typekey key
192.168.10.12:6379> type gw1
string
192.168.10.12:6379> type gao1
string
6.檢視當前資料庫中key的數量----dbsize
192.168.10.12:6379> keys *
1) "gw1"
2) "gw2"
3) "gao2"
4) "gao1"
192.168.10.12:6379> dbsize
(integer) 4
192.168.10.12:6379> select 1
OK
192.168.10.12:6379[1]> dbsize
(integer) 0
192.168.10.12:6379[1]> select 0
OK
192.168.10.12:6379> dbsize
(integer) 4
7.檢視某一個key是否存在----exists key
192.168.10.12:6379> exists gao1
(integer) 1
192.168.10.12:6379> exists ggao1
(integer) 0
三．刪除key----del key
192.168.10.12:6379> del gao1
(integer) 1
192.168.10.12:6379> get gao1
(nil)
192.168.10.12:6379> del gao1
(integer) 0
四．重新命名key----rename old new
192.168.10.12:6379> get gw1
"10"
192.168.10.12:6379> rename gw1 ggw1
OK
192.168.10.12:6379> get gw1
(nil)
192.168.10.12:6379> get ggw1
"10"
五．向key的字串追加拼接----append key value
192.168.10.12:6379> get gao1
"a"
192.168.10.12:6379> append gao1 b
(integer) 2
192.168.10.12:6379> get gao1
"ab"
六．獲取並重設某個key----getset key value
獲取該元素的值，並給該元素設定新值。
通常和incr搭配使用，比如一個mycount一直incr，然後達到某些情況需要清零，清零之前需要知道mycount的值
192.168.10.12:6379> get gao1
"ab"
192.168.10.12:6379> getset gao1 cd
"ab"
192.168.10.12:6379> get gao1
"cd"