17 redis -key设计原则

书签系统
create table book (
bookid int,
title char(20)
)engine myisam charset utf8;

insert into book values 
(5 , ‘PHP圣经‘),
(6 , ‘ruby实战‘),
(7 , ‘mysql运维‘),
(8, ‘ruby服务端编程‘);


create table tags (
tid int,
bookid int,
content char(20)
)engine myisam charset utf8;

insert into tags values 
(10 , 5 , ‘PHP‘),
(11 , 5 , ‘WEB‘),
(12 , 6 , ‘WEB‘),
(13 , 6 , ‘ruby‘),
(14 , 7 , ‘database‘),
(15 , 8 , ‘ruby‘),
(16 , 8 , ‘server‘);

# 既有web标签,又有PHP,同时还标签的书,要用连接查询

select * from tags inner join tags as t on tags.bookid=t.bookid
where tags.content=‘PHP‘ and t.content=‘WEB‘;


 
换成key-value存储
用kv 来存储
set book:5:title ‘PHP圣经‘
set book:6:title ‘ruby实战‘
set book:7:title ‘mysql运难‘
set book:8:title ‘ruby server’

sadd tag:PHP 5
sadd tag:WEB 5 6
sadd tag:database 7
sadd tag:ruby 6 8
sadd tag:SERVER 8

查: 既有PHP,又有WEB的书
Sinter tag:PHP tag:WEB  #查集合的交集

查: 有PHP或有WEB标签的书
Sunin tag:PHP tag:WEB

查:含有ruby,不含WEB标签的书
Sdiff tag:ruby tag:WEB #求差集




 
Redis key 设计技巧

1: 把表名转换为key前缀 如, tag:
2: 第2段放置用于区分区key的字段--对应mysql中的主键的列名,如userid
3: 第3段放置主键值,如2,3,4...., a , b ,c
4: 第4段,写要存储的列名

用户表 user  , 转换为key-value存储
--------------------------------------------------
  userid    username    passworde      email
--------------------------------------------------
   9         Lisi       1111111     lisi@163.com
--------------------------------------------------

set  user:userid:9:username lisi
set  user:userid:9:password 111111
set  user:userid:9:email   lisi@163.com

keys user:userid:9*


2 注意:
在关系型数据中,除主键外,还有可能其他列也步骤查询,
如上表中, username 也是极频繁查询的,往往这种列也是加了索引的.

转换到k-v数据中,则也要相应的生成一条按照该列为主的key-value
Set  user:username:lisi:uid  9  

这样,我们可以根据username:lisi:uid ,查出userid=9, 
再查user:9:password/email ...