redis中跟key相关的主要操作函数

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总结redis中跟key相关的常用函数

1、keys
语法:keys pattern
解释:查找所有匹配指定模式pattern的key

[root@nock ~]# redis-cli   
redis 127.0.0.1:6379> keys *  #所有key  
 1) "score"  
 2) "stu"  
 3) "score1"  
 4) "dest"  
 5) "lst.user"  
 6) "lst.tect"  
redis 127.0.0.1:6379> keys scor?   
1) "score"  
redis 127.0.0.1:6379> keys scor[ee1]  
1) "score"

2、randomkey
语法:randomkey
解释:返回一个随机key

redis 127.0.0.1:6379> randomkey  
"score"  
redis 127.0.0.1:6379> randomkey  
"list.user" 

3、exists
语法:exists key
解释:判断一个key是否存在

redis 127.0.0.1:6379> exists score  #key存在 返回1  
(integer) 1  
redis 127.0.0.1:6379> exists scorefda #key不存在 返回0  
(integer) 0 

4、type
语法:type key
解释:返回key所存储的值类型,返回值:none [key不存在],string,list ,set, zset和hash

redis 127.0.0.1:6379> type score  
zset  
redis 127.0.0.1:6379> type lst.user  
list  

5、expire
语法:expire key seconds
解释:设置key的生存时间,单位是秒,当key过期时,会被自动删除

redis 127.0.0.1:6379> expire dest 30  
(integer) 1  
redis 127.0.0.1:6379> expire dest1 30 # key不存在  
(integer) 0 

6、ttl
语法: ttl key
解释:得到key能存活时间,如果key不存在或没有设置生存时间时,返回-1

redis 127.0.0.1:6379> expire diff 100  
(integer) 1  
redis 127.0.0.1:6379> ttl diff  
(integer) 94  
redis 127.0.0.1:6379> ttl diff  
(integer) 92 

7、persist
语法:persist key
解释:移除给定key的生存时间

redis 127.0.0.1:6379> ttl diff  
(integer) 28  
redis 127.0.0.1:6379> persist diff  
(integer) 1  
redis 127.0.0.1:6379> ttl diff  
(integer) -1 

8、rename
语法:rename key newkey
解释:将key改名为newkey

redis 127.0.0.1:6379> smembers diff  
1) "zhangsan01"  
redis 127.0.0.1:6379> rename diff diff01  
OK  
redis 127.0.0.1:6379> smembers diff  
(empty list or set)  
redis 127.0.0.1:6379> smembers diff01  
1) "zhangsan01"  
redis 127.0.0.1:6379> rename diff diff01  
(error) ERR no such key

注意:当key和newkey相同或key不存在时,返回错误;当newkey已存在时,rename将覆盖旧值。

9、renamenx
语法:renamenx key newkey
解释:当且仅当newkey不存在时,改名key

redis 127.0.0.1:6379> renamenx diff01 stu  #stu存在  
(integer) 0  
redis 127.0.0.1:6379> renamenx diff01 diff #diff不存在  
(integer) 1

10、del
语法:del key [key ...]
解释:删除一个或多个key

redis 127.0.0.1:6379> del score1  
(integer) 1  
redis 127.0.0.1:6379> del union diff aa  #key aa 不存在  
(integer) 2

11、move
语法:move key db
解释:将key移动到指定db

redis 127.0.0.1:6379> smembers stu #默认0  
1) "zhangsan01"  
2) "wangwu"  
redis 127.0.0.1:6379> move stu 1  #移动到 1  
(integer) 1  
redis 127.0.0.1:6379> smembers stu  
(empty list or set)  
redis 127.0.0.1:6379> select 1 #选择db 1  
OK  
redis 127.0.0.1:6379[1]> smembers stu  
1) "zhangsan01"  
2) "wangwu"

12、sort
语法:sort key [BY pattern][LIMIT offset count] [GET pattern [GET pattern ...]][ASC|DESC] [ALPHA][STORE destination]
解释:返回或保持给定列表,集合,有序集合key中经过排序的元素

redis 127.0.0.1:6379> sort lst.tech limit 0 2 alpha desc #按字符集排序  
1) "tec06"  
2) "tec05"  
redis 127.0.0.1:6379> sort lst.stud  
1) "1"  
2) "2"  
3) "3"  
redis 127.0.0.1:6379> sort lst.stud desc   
1) "3"  
2) "2"  
3) "1"  
redis 127.0.0.1:6379> keys stu.*  
1) "stu.name.2"  
2) "stu.name.3"  
3) "stu.level.1"  
4) "stu.level.2"  
5) "stu.level.3"  
6) "stu.name.1"  
redis 127.0.0.1:6379> sort lst.stud by stu.level.[i] desc get stu.level.[/i] get stu.name.*  
1) "3"  
2) "admin"  
3) "2"  
4) "joe"  
5) "1"  
6) "jim"  
redis 127.0.0.1:6379> sort lst.stud by stu.level.[i] asc get stu.name.[/i]  
1) "jim"  
2) "joe"  
3) "admin"

sort虽然很“厉害”,但尽量不要让redis服务器来sort大量的数据。可以通过设定阀值减少要sort的数据,或把排序操作向前移,在web服务器或各个应用上来sort。

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