Redis系列-key相关主要操作函数

这篇blog主要总结下，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@xsf001 ~]# 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.* desc get stu.level.* 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.* asc get stu.name.*
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。