Fan pays attention to the design of database table

CREATE TABLE relation (id PRIMARY KEY AUTO_INCREMENT, //主键，自增from_user_id big integer, // 用户 A 的 idto_user_id big integer,// 用户 B 的 Idrel_type enum(1,2) //关注数据);

Pull/fans/followers, in the database, the number that is stored is a mapping relationship. For example, the black is 1, the fan/concern is a thing, is 2. So, the key data in a record is:

• from_user_idWhich user initiated this record?

• to_user_idWhich user is the recipient of this record?

• rel_typeWhat did the initiator do to the recipient? Types of Things to save

Examples of scenarios:

User A is concerned about user B

Insert data:

INSERT INTO relation (rel_type, from_user_id, to_user_id) VALUES(2, A.id, B.id)

Number of fans for user A:

select COUNT(*) from relation where rel_type=2 and to_user_id=A.id;

Fan pays attention to the design of database table