redis--hashes类型及操作

r囧r小猫 2022-07-16 00:27 149阅读 0赞

# hashes类型及操作 #

redis hash是一个string类型的field和value的映射表。hash特别适用于存储对象。相较于将对象的每个字段存成单个string类型。将一个对象存储在hash类型中会占用更少的内存，并且可以更方便的存取整个对象。

# hset #

设置hash field为指定值，如果key不存在，则先创建。

例如：设置一个id为001的用户，name是ysy

127.0.0.1:6379> hset user:001 name ysy
    (integer) 1
    127.0.0.1:6379> hget user:001 name
    "ysy"

# hsetnx #

设置hash field为指定值，如果key不存在，则先创建，如果存在则返回0.

127.0.0.1:6379> hset user:001 name ysy
    (integer) 1
    127.0.0.1:6379> hget user:001 name
    "ysy"
    127.0.0.1:6379> hsetnx user:001 name 123
    (integer) 0
    127.0.0.1:6379> hsetnx user:002 name 002
    (integer) 1
    127.0.0.1:6379> hget user:002 name
    "002"

# hmset #

同时设置hash的多个field。

127.0.0.1:6379> hmset user:003 name ysy age 21 sex 1
    OK
    127.0.0.1:6379> hget user:003 name
    "ysy"
    127.0.0.1:6379> hget user:003 age
    "21"
    127.0.0.1:6379> hget user:003 sex
    "1"

# hget #

获取指定的hash field

# hmget #

获取全部指定的hash field

127.0.0.1:6379> hmget user:003 name age sex
    1) "ysy"
    2) "21"
    3) "1"

# hincrby #

给hash field加上指定值

127.0.0.1:6379> hget user:003 age
    "21"
    127.0.0.1:6379> hincrby user:003 age 5
    (integer) 26
    127.0.0.1:6379> hincrby user:003 age 5
    (integer) 31
    127.0.0.1:6379> hincrby user:003 age -5
    (integer) 26

# hexists #

测试指定的field是否存在

127.0.0.1:6379> hexists user:003 age
    (integer) 1
    127.0.0.1:6379> hexists user:003 name
    (integer) 1
    127.0.0.1:6379> hexists user:003 sex
    (integer) 1
    127.0.0.1:6379> hexists user:003 old
    (integer) 0

# hlen #

返回指定的hash的field数量

127.0.0.1:6379> hlen user:003
    (integer) 3

# hdel #

删除指定的hash field

127.0.0.1:6379> hget user:003 age
    "26"
    127.0.0.1:6379> hdel user:003 age
    (integer) 1
    127.0.0.1:6379> hexists user:003 age
    (integer) 0
    127.0.0.1:6379> hget user:003 age
    (nil)

# hkeys #

返回hash所有的field

127.0.0.1:6379> hkeys user:003
    1) "name"
    2) "sex"

# hvals #

返回hash所有的value

127.0.0.1:6379> hkeys user:003
    1) "name"
    2) "sex"
    127.0.0.1:6379> hvals user:003
    1) "ysy"
    2) "1"

# hgetall #

获取某个hash中全部的field及value

127.0.0.1:6379> hgetall user:003
    1) "name"
    2) "ysy"
    3) "sex"
    4) "1"