如何在redis中建立多对多关系

Question

在关系数据库中,我有一个用户表,一个类别表和一个多对多关系的用户类别表.在redis中有这种结构的更好的形式是什么？

Answer 1

使用Redis,关系通常由集合表示.集合可用于表示单向关系,因此每个对象需要一个集合来表示多对多关系.

尝试将关系数据库模型与Redis数据结构进行比较是没有用的.使用Redis,一切都以非规范化的方式存储.

例:

# Here are my categories
> hmset category:1 name cinema  ... more fields ...
> hmset category:2 name music   ... more fields ...
> hmset category:3 name sports  ... more fields ...
> hmset category:4 name nature  ... more fields ...

# Here are my users
> hmset user:1 name Jack   ... more fields ...
> hmset user:2 name John   ... more fields ...
> hmset user:3 name Julia  ... more fields ...

# Let's establish the many-to-many relationship
# Jack likes cinema and sports
# John likes music and nature
# Julia likes cinema, music and nature

# For each category, we keep a set of reference on the users
> sadd category:1:users 1 3
> sadd category:2:users 2 3
> sadd category:3:users 1
> sadd category:4:users 2 3

# For each user, we keep a set of reference on the categories
> sadd user:1:categories 1 3
> sadd user:2:categories 2 4
> sadd user:3:categories 1 2 4

一旦我们有了这个数据结构,就很容易使用set代数查询它:

# Categories of Julia
> smembers user:3:categories
1) "1"
2) "2"
3) "4"

# Users interested by music
> smembers category:2:users
1) "2"
2) "3"

# Users interested by both music and cinema
> sinter category:1:users category:2:users
1) "3"