# 测试数据
redis> HGETALL abbr
1) "a"
2) "apple"
3) "b"
4) "banana"
5) "c"
6) "cat"
7) "d"
8) "dog"
# 删除单个域
redis> HDEL abbr a
(integer) 1
# 删除不存在的域
redis> HDEL abbr not-exists-field
(integer) 0
# 删除多个域
redis> HDEL abbr b c
(integer) 2
redis> HGETALL abbr
1) "d"
2) "dog"
redis> HEXISTS phone myphone
(integer) 0
redis> HSET phone myphone nokia-1110
(integer) 1
redis> HEXISTS phone myphone
(integer) 1
# 域存在
redis> HSET site redis redis.com
(integer) 1
redis> HGET site redis
"redis.com"
# 域不存在
redis> HGET site mysql
(nil)
redis> HSET people jack "Jack Sparrow"
(integer) 1
redis> HSET people gump "Forrest Gump"
(integer) 1
redis> HGETALL people
1) "jack" # 域
2) "Jack Sparrow" # 值
3) "gump"
4) "Forrest Gump"
# increment 为正数
redis> HEXISTS counter page_view # 对空域进行设置
(integer) 0
redis> HINCRBY counter page_view 200
(integer) 200
redis> HGET counter page_view
"200"
# increment 为负数
redis> HGET counter page_view
"200"
redis> HINCRBY counter page_view -50
(integer) 150
redis> HGET counter page_view
"150"
# 尝试对字符串值的域执行HINCRBY命令
redis> HSET myhash string hello,world # 设定一个字符串值
(integer) 1
redis> HGET myhash string
"hello,world"
redis> HINCRBY myhash string 1 # 命令执行失败,错误。
(error) ERR hash value is not an integer
redis> HGET myhash string # 原值不变
"hello,world"
# 值和增量都是普通小数
redis> HSET mykey field 10.50
(integer) 1
redis> HINCRBYFLOAT mykey field 0.1
"10.6"
# 值和增量都是指数符号
redis> HSET mykey field 5.0e3
(integer) 0
redis> HINCRBYFLOAT mykey field 2.0e2
"5200"
# 对不存在的键执行 HINCRBYFLOAT
redis> EXISTS price
(integer) 0
redis> HINCRBYFLOAT price milk 3.5
"3.5"
redis> HGETALL price
1) "milk"
2) "3.5"
# 对不存在的域进行 HINCRBYFLOAT
redis> HGETALL price
1) "milk"
2) "3.5"
redis> HINCRBYFLOAT price coffee 4.5 # 新增 coffee 域
"4.5"
redis> HGETALL price
1) "milk"
2) "3.5"
3) "coffee"
4) "4.5"
# 哈希表非空
redis> HMSET website google www.google.com yahoo www.yahoo.com
OK
redis> HKEYS website
1) "google"
2) "yahoo"
# 空哈希表/key不存在
redis> EXISTS fake_key
(integer) 0
redis> HKEYS fake_key
(empty list or set)
redis> HSET db redis redis.com
(integer) 1
redis> HSET db mysql mysql.com
(integer) 1
redis> HLEN db
(integer) 2
redis> HSET db mongodb mongodb.org
(integer) 1
redis> HLEN db
(integer) 3
redis> HMSET pet dog "doudou" cat "nounou" # 一次设置多个域
OK
redis> HMGET pet dog cat fake_pet # 返回值的顺序和传入参数的顺序一样
1) "doudou"
2) "nounou"
3) (nil) # 不存在的域返回nil值
redis> HMSET website google www.google.com yahoo www.yahoo.com
OK
redis> HGET website google
"www.google.com"
redis> HGET website yahoo
"www.yahoo.com"
redis> HSET website google "www.g.cn" # 设置一个新域
(integer) 1
redis> HSET website google "www.google.com" # 覆盖一个旧域
(integer) 0
redis> HSETNX nosql key-value-store redis
(integer) 1
redis> HSETNX nosql key-value-store redis # 操作无效,域 key-value-store 已存在
(integer) 0
# 非空哈希表
redis> HMSET website google www.google.com yahoo www.yahoo.com
OK
redis> HVALS website
1) "www.google.com"
2) "www.yahoo.com"
# 空哈希表/不存在的key
redis> EXISTS not_exists
(integer) 0
redis> HVALS not_exists
(empty list or set)