如何在typeorm中创建如何创建多对多关系[NestJS]

// user.entity.ts
import { Entity, PrimaryGeneratedColumn, Column, ManyToMany, JoinTable } from 'typeorm';
import { Role } from './role.entity';

@Entity()
export class User {
  @PrimaryGeneratedColumn()
  id: number;

  @Column()
  name: string;

  @ManyToMany(() => Role)
  @JoinTable()
  roles: Role[];
}

// role.entity.ts
import { Entity, PrimaryGeneratedColumn, Column, ManyToMany } from 'typeorm';
import { User } from './user.entity';

@Entity()
export class Role {
  @PrimaryGeneratedColumn()
  id: number;

  @Column()
  name: string;

  @ManyToMany(() => User, user => user.roles)
  users: User[];
}

// app.module.ts
import { Module } from '@nestjs/common';
import { TypeOrmModule } from '@nestjs/typeorm';
import { User } from './user.entity';
import { Role } from './role.entity';

@Module({
  imports: [
    TypeOrmModule.forRoot({
      // 配置typeorm连接数据库的参数
      // ...
      entities: [User, Role], // 将实体类添加到typeorm的实体列表中
    }),
  ],
})
export class AppModule {}

// user.service.ts
import { Injectable } from '@nestjs/common';
import { InjectRepository } from '@nestjs/typeorm';
import { Repository } from 'typeorm';
import { User } from './user.entity';

@Injectable()
export class UserService {
  constructor(
    @InjectRepository(User)
    private userRepository: Repository<User>,
  ) {}

  async getUserRoles(userId: number): Promise<Role[]> {
    const user = await this.userRepository.findOne(userId, { relations: ['roles'] });
    return user.roles;
  }
}