我有用户,我想实现添加 friend 。
因此,这会创建多对多关系,如何在使用相同实例时使用 sequelize 创建多对多关系?
User.belongsToMany(User, {as: "friends", through: "friends})
但我不知道如何处理外键以及它们将被称为什么
最佳答案
下面使用 "sequelize": "^5.21.3"
的示例:
import { sequelize } from '../../db';
import { Model, DataTypes, BelongsToManyAddAssociationMixin } from 'sequelize';
class User extends Model {
public getFriends!: BelongsToManyAddAssociationMixin<User, string>;
}
User.init(
{
name: DataTypes.STRING,
},
{ sequelize, modelName: 'users' },
);
User.belongsToMany(User, { as: 'friends', through: 'user_friends' });
(async function test() {
try {
await sequelize.sync({ force: true });
// seed
const friendsOfUser1 = [{ name: 'james' }, { name: 'elsa' }];
const friendsOfUser2 = [{ name: 'jane' }, { name: 'mike' }];
await User.bulkCreate(
[
{ name: 'jeremy', friends: friendsOfUser1 },
{ name: 'lynne', friends: friendsOfUser2 },
],
{ include: [{ model: User, as: 'friends' }] },
);
const jeremy = await User.findOne({ where: { name: 'jeremy' } });
const firendsOfJeremy = await jeremy.getFriends();
console.log(firendsOfJeremy);
} catch (error) {
console.log(error);
} finally {
await sequelize.close();
}
})();
它将创建存储对象 ID 的表
user_friends
。查看数据库中的数据记录:node-sequelize-examples=# select * from user_friends;
userId | friendId
--------+----------
1 | 3
1 | 4
2 | 5
2 | 6
(4 rows)
node-sequelize-examples=# select * from users;
id | name
----+--------
1 | jeremy
2 | lynne
3 | james
4 | elsa
5 | jane
6 | mike
(6 rows)
您可以调用
userInstance.getFriends()
来获取一些用户的 friend 。
关于javascript - 使用同一实例建立多对多关系,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/60921775/