Redis入门一

Redis支持的数据类型：

• Binary-safe strings： 字符串
• Lists：有序列表；底层维护的是一个链表结构，包含字符串元素的集合，有顺序、根据插入顺序而定
• Sets ：无序集合；元素不可重复、无序 集合里面的元素是字符串
• Sorted sets：有序集合；和Sets 不同集合里面每个元素都关联了一个 floating number value 叫做score， 集合会根据score来排序
• Hashes：散列；类似java的hashMap 由字段-字段值组成， 都是字符串。composed of fields associated with values. Both the field and the value are strings
• Bit arrays：
• HyperLogLogs

Redis keys 键值的选择

• Very long keys are not a good idea 键值不能太长
• Very short keys are often not a good idea.键值太短也不太好
• Try to stick with a schema. 键值应该按照一种约定的模式来命名，如： "object-type:id" is a good idea, as in "user:1000". Dots or dashes are often used for multi-word fields, as in "comment:1234:reply.to" or "comment:1234:reply-to".多个单词用点或者斜线分隔
• The maximum allowed key size is 512 MB.键值最长不能超过512 MB

Lists：Redis的Lists底层采用的是链表Link lists, 链表的优点：
1.插入速度快、时间复杂度是1 Redis Lists are implemented with linked lists because for a database system it is crucial to be able to add elements to a very long list in a very fast way. Another strong advantage, as you‘ll see in a moment, is that Redis Lists can be taken at constant length in constant time.
缺点：数据量大时访问速度会慢，如果想要快的访问速度可以采用 sort set