redis缓存数据库

  
  APPEND key value   
  summary: Append a value to a key         key不存在时创建key，赋值value，存在key时，将value追加到原来的值上
  since: 2.0.0

  BITCOUNT key [start end]
  summary: Count set bits in a string       对应的值中二进制表示中的1的个数
  since: 2.6.0

  BITFIELD key [GET type offset] [SET type offset value] [INCRBY type offset increment] [OVERFLOW WRAP|SAT|FAIL]
  summary: Perform arbitrary bitfield integer operations on strings   
  since: 3.2.0

  BITOP operation destkey key [key ...]
  summary: Perform bitwise operations between strings
  since: 2.6.0

  BITPOS key bit [start] [end]
  summary: Find first bit set or clear in a string
  since: 2.8.7

  DECR key
  summary: Decrement the integer value of a key by one
  since: 1.0.0

  DECRBY key decrement
  summary: Decrement the integer value of a key by the given number
  since: 1.0.0

  GET key
  summary: Get the value of a key           获取key所对应的值
  since: 1.0.0
  
  GETBIT key offset
  summary: Returns the bit value at offset in the string value stored at key           获取key所对应的值的二进制表示的某位的值（0或1）
  since: 2.2.0

  GETRANGE key start end
  summary: Get a substring of the string stored at a key      获取子序列（类似切片，但根据字节获取，非字符，对于汉字和数字注意）
  since: 2.4.0

  GETSET key value
  summary: Set the string value of a key and return its old value     设置新值并获取原来的值
  since: 1.0.0

  INCR key
  summary: Increment the integer value of a key by one      自增1，必须为整数。
  since: 1.0.0

  INCRBY key increment
  summary: Increment the integer value of a key by the given amount  自增对应的值，必须为整数
  since: 1.0.0

  INCRBYFLOAT key increment
  summary: Increment the float value of a key by the given amount  自增对应的值，浮点数
  since: 2.6.0

  MGET key [key ...]
  summary: Get the values of all the given keys   批量获取值  mget k1 k2
  since: 1.0.0

  MSET key value [key value ...]
  summary: Set multiple keys to multiple values    批量设置值   mset k1 v1 k2 v2
  since: 1.0.1

  MSETNX key value [key value ...]
  summary: Set multiple keys to multiple values, only if none of the keys exist
  since: 1.0.1

  PSETEX key milliseconds value
  summary: Set the value and expiration in milliseconds of a key            设置值，过期时间（毫秒）
  since: 2.6.0

  SET key value [EX seconds] [PX milliseconds] [NX|XX]  
  summary: Set the string value of a key                 创建键值对，存在则修改
  since: 1.0.0

  SETBIT key offset value
  summary: Sets or clears the bit at offset in the string value stored at key     对应值的二进制表示的某位进行操作，设置为0或1
  since: 2.2.0

  SETEX key seconds value             
  summary: Set the value and expiration of a key       key已存在，设置值
  since: 2.0.0

  SETNX key value                               
  summary: Set the value of a key, only if the key does not exist   只有key不存在时，设置键值对
  since: 1.0.0

  SETRANGE key offset value
  summary: Overwrite part of a string at key starting at the specified offset     修改字符串内容，从指定字符串索引开始向后替换（新值太长时，则向后添加）
  since: 2.2.0

  STRLEN key
  summary: Get the length of the value stored in a key          返回name对应值的字节长度（一个汉字3个字节）
  since: 2.2.0