【问题标题】：Redis Data Modeling for Many-To-Many relationship多对多关系的 Redis 数据建模
【发布时间】：2019-04-14 13:06:15
【问题描述】：

查看链接 - how to have relations many to many in redis。我尝试使用 Spring Data Redis HashRedis 类对此进行建模。这个示例模型....

# 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，就很容易使用集合代数来查询它：

朱莉娅的类别

> 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"

用户.java

@Data
@AllArgsConstructor
@NoArgsConstructor
@Builder
@RedisHash("users")
public class User {
    @Id
    private String userId;
    private String firstName;
    private String emailId;
    private List<Category> categories;
}

Category.java

@Data
@AllArgsConstructor
@NoArgsConstructor
@Builder
@RedisHash("category")
public class Category {
    @Id
    private String categoryId;
    private String name;
    private String type;

    private List<User> users;
}

RedisExampleBootApplication.java

@SpringBootApplication
public class RedisExampleBootApplication implements CommandLineRunner{
    @Autowired CategoryRepository categoryRepository;
    @Autowired UserRepository userRepository;

    public static void main(String[] args) {
        SpringApplication.run(RedisExampleBootApplication.class, args);
    }

    @Override
    public void run(String... args) throws Exception {  

        User jack = User.builder().firstName("Jack").emailId("jack@gmail.com").build();
        User john = User.builder().firstName("John").emailId("john@gmail.com").build();
        User julia  = User.builder().firstName("Julia ").emailId("julia @gmail.com").build();

        Category cinema = Category.builder().name("Cinema").type("Entertainment").users(Arrays.asList(jack, julia)).build();
        Category sports = Category.builder().name("Sports").type("Play Game").users(Arrays.asList(jack)).build();

        Category music = Category.builder().name("Music").type("Sounds").users(Arrays.asList(john, julia)).build();
        Category nature = Category.builder().name("Nature").type("Wild Life").users(Arrays.asList(john, julia)).build();

        categoryRepository.save(cinema);
        categoryRepository.save(sports);
        categoryRepository.save(music);
        categoryRepository.save(nature);



        Category myCinema = Category.builder().name("Cinema").name("Entertainment").build();
        Category mySport = Category.builder().name("Sports").name("Play Game").build();
        Category myMusic = Category.builder().name("Music").name("Sound").build();
        Category myNature = Category.builder().name("Nature").name("Wild Life").build();


        User myJack = User.builder().firstName("Jack").emailId("jack@gmail.com").categories(Arrays.asList(myCinema, mySport)).build();
        User myJohn = User.builder().firstName("John").emailId("john@gmail.com").categories(Arrays.asList(myMusic, myNature)).build();
        User myJulia  = User.builder().firstName("Julia ").emailId("julia @gmail.com").categories(Arrays.asList(myCinema,myMusic, myNature)).build();

        userRepository.save(myJack);
        userRepository.save(myJohn);
        userRepository.save(myJulia);
    }
}

这是数据建模的结果

127.0.0.1:6379> KEYS *
1) "category:0bcba339-9a3e-46e3-b33c-877f8d15595f"
2) "category:4d2b8d10-83de-41fa-8a33-93f30a6f9ffc"
3) "category:f756f18c-53e4-4a20-9a42-ad08b537f380"
4) "category"
5) "users:644d0adc-f0cf-4ba1-8d6b-d6f47145e5e7"
6) "users:8aa5c578-4e05-4ae9-8f80-d10b789e0877"
7) "users:825ab11b-803a-4e4f-a72d-e6b42b98007c"
8) "category:54a56102-5836-41bf-86a8-c82b3f12d3cf"
9) "users"
127.0.0.1:6379>

我没有在任何地方使用过@Indexed，因为目前我没有使用任何findBy 方法，但这不是问题所在。我只需要确认如何对数据建模？还是 POJO 建模正确？

HGETALL 用户：8aa5c578-4e05-4ae9-8f80-d10b789e0877

userId 8aa5c578-4e05-4ae9-8f80-d10b789e0877
_class com.example.model.User
firstName Jack
emailId jack@gmail.com
categories.[1].name Play Game
categories.[0].name Entertainment

【问题讨论】：

标签： spring redis jedis spring-data-redis

【解决方案1】：

我在同一个链接上发布了另一个答案。因为我还没有收到任何专家的任何 cmets。如果有人这样做，我将非常有帮助。

我让模型类就这么简单，只是创建了一个键来保存它们之间的关系。我需要 Redis 专家指导如何继续进行。

这很简单，我猜命令在做什么，我们也在做同样的事情。

// Category Details
Category c1 = Category.builder().id("c1").name("Cinema").build();
Category c2 = Category.builder().id("c2").name("Sports").build();
Category c3 = Category.builder().id("c3").name("Music").build();
Category c4 = Category.builder().id("c4").name("Nature").build();

redisTemplate.opsForSet().add("category:1", new ObjectMapper().writeValueAsString(c1));
redisTemplate.opsForSet().add("category:2", new ObjectMapper().writeValueAsString(c2));
redisTemplate.opsForSet().add("category:3", new ObjectMapper().writeValueAsString(c3));
redisTemplate.opsForSet().add("category:4", new ObjectMapper().writeValueAsString(c4));

// User 
User u1 = User.builder().id("u1").firstName("Chris").emailId("chris.rogers@gmail.com").build(); //1
User u2 = User.builder().id("u2").firstName("John").emailId("john.doe@gmail.com").build();  //2
User u3 = User.builder().id("u3").firstName("Julia").emailId("julia.cox@gmail.com").build(); //3

redisTemplate.opsForSet().add("user:1", new ObjectMapper().writeValueAsString(u1));
redisTemplate.opsForSet().add("user:2", new ObjectMapper().writeValueAsString(u2));
redisTemplate.opsForSet().add("user:3", new ObjectMapper().writeValueAsString(u3));

redisTemplate.opsForSet().add("category:1:users", "1","3");
redisTemplate.opsForSet().add("category:2:users", "2","3");
redisTemplate.opsForSet().add("category:3:users", "1");
redisTemplate.opsForSet().add("category:4:users", "2","3");

redisTemplate.opsForSet().add("user:1:categories", "1","3");
redisTemplate.opsForSet().add("user:2:categories", "2", "4" );
redisTemplate.opsForSet().add("user:3:categories", "1", "2", "4");

注意：您可以使用UUID 动态管理密钥。

【讨论】：

【解决方案2】：

我能够解决这个问题。您只需将关系保持在单独的@RedishHash 类中并给出PK（Redis 中没有PK，而是说unique key）并使用类别中的PK 和用户中的PK 并用@987654326 注释它们@，以便您可以使用Repository 模式进行自定义搜索。

通过这种方式，您只需维护 Categories 的列表以获取单个 User 并维护 Users 以获取单个 category。这里只使用了单映射。

就像为Category 保存数据一样，为Category 保存user。例如 - 假设User-1对Category-1感兴趣，User-2对Category-1 and 2感兴趣，对User-3感兴趣

Category-3
Category-1 save User-1
Category-1 save User-2

Category-2 save User-2
Category-2 save User-3

完成！！这很好用。这是另一种方法，简单地使用CRUDRepository 模式而不使用RedisTemplate。

【讨论】：