四、Redis哈希（Hash）类型参考记录
Redis是采用字典结构以键值对的形式存储数据的。哈希类型的键值也是一种字典结构，储存了字段和字段值的映射，字段值能是字符串，不支持其他数据类型。
哈希类型不能嵌套其他数据类型。
一个哈希类型键可以包含至多232-1个字段。
哈希类型适合存储对象：使用对象类别和ID构成键名，使用字段表示对象的属性，字段值则存储属性值。如下案例：存储ID为1的文章对象，分别使用作者、时间、内容这3个字段来存储文章的信息。
基本命令 取值/赋值
hset 将哈希表中key中的field的值设置为value
语法：hset key field value
<span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"><span style="box-sizing: border-box;color: rgb(98, 151, 85) !important"># hset设置单个值</span></span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"><span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">127</span>.0.0.1:6379> hset car price <span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">10000</span></span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px">(integer) <span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">1</span></span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"><span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">127</span>.0.0.1:6379> hset car name BMW</span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px">(integer) <span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">1</span></span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"><span style="box-sizing: border-box;color: rgb(98, 151, 85) !important"># 字段已存在，执行更新操作，返回0</span></span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"><span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">127</span>.0.0.1:6379> hset car name BMWM</span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px">(integer) <span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">0</span></span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"><span style="box-sizing: border-box"></span></span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"><span style="box-sizing: border-box;color: rgb(98, 151, 85) !important"># 设置多个field-value </span></span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"><span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">127</span>.0.0.1:6379> hset article author ziruchu time <span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">2020</span></span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px">(integer) <span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">2</span></span>
若哈希表不存在，则创建；若字段已存在，则新值覆盖旧值。
hset不区分插入还是更新操作，当执行插入操作时（字段不存在），hset命令返回1；当执行更新操作时（字段存在），hset命令返回0。键不存在时，hset会自动创建该键。
hmset 将多个field-value对设置到哈希表key中
语法：hmset key field1 value1 [field2 value2 ...]
<span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"><span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">127</span>.0.0.1:6379> hmset <span style="box-sizing: border-box;color: rgb(232, 191, 106) !important">cat</span> color white age <span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">2</span></span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px">OK</span>
hsetnx field字段不存在时，设置哈希表字段的值
语法：hsetnx key field value
<span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"><span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">127</span>.0.0.1:6379> hsetnx article1 time <span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">2020</span></span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px">(integer) <span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">1</span></span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"><span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">127</span>.0.0.1:6379> hsetnx article1 author <span style="box-sizing: border-box;color: rgb(152, 195, 121) !important">'xiao bai'</span></span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px">(integer) <span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">1</span></span>
hget 获取一个存储在哈希表中指定字段的值
语法：hget key filed
<span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"><span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">127</span>.0.0.1:6379> hget <span style="box-sizing: border-box;color: rgb(232, 191, 106) !important">cat</span> color</span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"><span style="box-sizing: border-box;color: rgb(152, 195, 121) !important">"white"</span></span>
hmget 获取哈希表指定字段的值
语法：hmget key field [field1,field2 ...]
<span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"><span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">127</span>.0.0.1:6379> hmget <span style="box-sizing: border-box;color: rgb(232, 191, 106) !important">cat</span> color age</span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"><span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">1</span>) <span style="box-sizing: border-box;color: rgb(152, 195, 121) !important">"white"</span></span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"><span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">2</span>) <span style="box-sizing: border-box;color: rgb(152, 195, 121) !important">"2</span></span>
hgetall 获取指定哈希表指定key的所有字段和值
语法：hgetall key
<span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"><span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">127</span>.0.0.1:6379> hgetall <span style="box-sizing: border-box;color: rgb(232, 191, 106) !important">cat</span></span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"><span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">1</span>) <span style="box-sizing: border-box;color: rgb(152, 195, 121) !important">"color"</span></span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"><span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">2</span>) <span style="box-sizing: border-box;color: rgb(152, 195, 121) !important">"white"</span></span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"><span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">3</span>) <span style="box-sizing: border-box;color: rgb(152, 195, 121) !important">"age"</span></span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"><span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">4</span>) <span style="box-sizing: border-box;color: rgb(152, 195, 121) !important">"2"</span></span>
其他命令
hexists 判断一个字段是否存在
语法：hexists key field
<span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"><span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">127</span>.0.0.1:6379> hexists <span style="box-sizing: border-box;color: rgb(232, 191, 106) !important">cat</span> age</span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px">(integer) <span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">1</span></span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"><span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">127</span>.0.0.1:6379> hexists <span style="box-sizing: border-box;color: rgb(232, 191, 106) !important">cat</span> a</span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px">(integer) <span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">0</span></span>
hexists判断一个字段是否存在，存在返回1，不存在返回0
hdel 删除一个或多个字段
语法：hdel key field1 [field2 ...]
<span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"><span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">127</span>.0.0.1:6379> hdel car name</span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px">(integer) <span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">1</span></span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"><span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">127</span>.0.0.1:6379> hdel <span style="box-sizing: border-box;color: rgb(232, 191, 106) !important">cat</span> color age</span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px">(integer) <span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">2</span></span>
返回被删除字段的个数
hkeys 获取所有字段
语法：hkeys key
<span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"><span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">127</span>.0.0.1:6379> hkeys article</span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"><span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">1</span>) <span style="box-sizing: border-box;color: rgb(152, 195, 121) !important">"author"</span></span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"><span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">2</span>) <span style="box-sizing: border-box;color: rgb(152, 195, 121) !important">"time"</span></span>
hvals 获取所有值
语法：hvals key
<span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"><span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">127</span>.0.0.1:6379> hvals article</span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"><span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">1</span>) <span style="box-sizing: border-box;color: rgb(152, 195, 121) !important">"ziruchu"</span></span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"><span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">2</span>) <span style="box-sizing: border-box;color: rgb(152, 195, 121) !important">"2020"</span></span>
hlen 获取字段数量
语法：hlen key
<span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"><span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">127</span>.0.0.1:6379> hlen article</span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px">(integer) <span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">2</span></span>
hincrby 为哈希表key中指定字段的整数值加上增量值
语法：hincrby key field 增量值
<span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"><span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">127</span>.0.0.1:6379> hmset number id <span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">1</span> total <span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">3</span></span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px">OK</span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"><span style="box-sizing: border-box"></span></span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"><span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">127</span>.0.0.1:6379> hincrby number id <span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">10</span></span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px">(integer) <span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">11</span></span>
hincrbyfloat 为哈希表key中指定字段的浮点数值加上增量值
语法：hincrbyfloat key field 增量值
<span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"><span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">127</span>.0.0.1:6379> hincrbyfloat number total <span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">10</span>.34</span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"><span style="box-sizing: border-box;color: rgb(152, 195, 121) !important">"13.34"</span></span>
hscan 迭代哈希表中的键值对
语法：hsan key cursor [match pattern] [count count]
参数：
- cursor 游标
- pattern 匹配模式
- count 指定从数据集返回多少元素，默认10
<span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"><span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">127</span>.0.0.1:6379> hscan article <span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">0</span> match <span style="box-sizing: border-box;color: rgb(152, 195, 121) !important">"a*"</span></span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"><span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">1</span>) <span style="box-sizing: border-box;color: rgb(152, 195, 121) !important">"0"</span></span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"><span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">2</span>) <span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">1</span>) <span style="box-sizing: border-box;color: rgb(152, 195, 121) !important">"author"</span></span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"> <span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">2</span>) <span style="box-sizing: border-box;color: rgb(152, 195, 121) !important">"ziruchu"</span></span>
我是小白，期待和优秀的你一起同行!
小白
2020年08月31日
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