NestJS - TypeORM - 多对一实体未定义

Question

我正在尝试链接到实体 Child 和 Client

所以我创建了 2 个实体：

// src/children/child.entity.ts

@Entity()
export class Child extends BaseEntity {

  @PrimaryGeneratedColumn()
  id: number;

  @Column()
  firstname: string;

  @Column()
  lastname: string;

  @ManyToOne(type => Client, client => client.children, { eager: false })
  client: Client

  @Column()
  clientId: number;
}

和

// src/clients/client.entity.ts

@Entity()
export class Client extends BaseEntity {

  @PrimaryGeneratedColumn()
  id: number;

  @Column()
  firstname: string;

  @Column()
  lastname: string;

  @OneToMany(type => Child, child => child.client, { eager: true })
  children: Child[];

}

我可以创建一个client 和一个child。当我得到一个client 时，我可以检索他所有的children。

但我无法用child 检索client：

例如，在children.controller.ts

当我访问http://locahost:3000/children/1/parent时

我上了控制台：

我真的被卡住了，因为我不知道如何解决这个问题。

这里是children.module.ts

import { Module } from '@nestjs/common';
import { ChildrenController } from './children.controller';
import { ChildrenService } from './children.service';
import { TypeOrmModule } from '@nestjs/typeorm';
import { ChildRepository } from './child.repository';
import { ClientRepository } from 'src/clients/client.repository';
import { ClientsService } from 'src/clients/clients.service';
import { Client } from 'src/clients/client.entity';

@Module({
  imports: [
    TypeOrmModule.forFeature([ChildRepository, ClientRepository, Client]),
  ],
  controllers: [ChildrenController],
  providers: [ChildrenService, ClientsService]
})
export class ChildrenModule {}

这里是typeorm.config

import { TypeOrmModuleOptions } from '@nestjs/typeorm';

export const typeOrmConfig: TypeOrmModuleOptions = {
  type: 'postgres',
  host: 'localhost',
  port: 5432,
  username: 'myusername',
  password: '',
  database: 'mydatabase',
  entities: [__dirname + '/../**/*.entity.{js,ts}'],
  synchronize: true,
}

编辑 1：

children.controller.ts

// src/children/children.controller.ts

@Controller('children')
export class ChildrenController {

  constructor(
    private childrenService: ChildrenService,
    private clientsService: ClientsService
  ) {}

  @Get('/:id')
  async getChild(id: number): Promise<Child> {
    return await this.childrenService.getChild(id);
  }
}

children.service.ts

// src/children/children.service.ts

@Injectable()
export class ChildrenService {
  constructor(
    @InjectRepository(ChildRepository)
    private childRepository: ChildRepository,
    @InjectRepository(ClientRepository)
    private clientRepository: ClientRepository
  ) {}

  async getChild(id: number): Promise<Child> {
    return await this.childRepository.findOne(id)
  }
}

谢谢你的帮助????

Answer 1

在我看来，您忘记在此关系的 ManyToOne 端添加 @JoinColumn()。尝试以这种方式增强您的代码

@Entity()
export class Child extends BaseEntity {

  @PrimaryGeneratedColumn()
  id: number;

  @Column()
  firstname: string;

  @Column()
  lastname: string;

  @ManyToOne(type => Client, client => client.children, { eager: false })
  @JoinColumn()
  client: Client

  @Column()
  clientId: number;
}

另外，请注意eager 参数。如果它设置为true，即使您不需要手动加载此关系也会自动加载，否则您必须指定要加载关系。 尝试像这样增强children.service.ts：

  async getChild(id: number): Promise<Child> {
    return await this.childRepository.findOne(id, {
      relations: ['client']
    })
  }

或者您可以将此关系设置为eager，每次加载Child时都会自动加载

  @ManyToOne(type => Client, client => client.children, { eager: true })
  @JoinColumn()
  client: Client

Answer 2

正如@Yevhenii 提到的，您忘记添加 JoinColumn 但您必须指定客户列：

    @Entity()
export class Child extends BaseEntity {

  @PrimaryGeneratedColumn()
  id: number;

  @Column()
  firstname: string;

  @Column()
  lastname: string;

  @ManyToOne(()=> Client, (client) => client.children, { eager: false })
  @JoinColumn([{ name: "clientId", referencedColumnName: "id" }])
  client: Client

  @Column()
  clientId: number;
}

不要犹豫，告诉我结果。