如何在typeorm + nestjs中子实体对象中获取父ID

import { Entity, PrimaryGeneratedColumn, Column, OneToMany } from 'typeorm';
import { ChildEntity } from './child.entity';

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

  @Column()
  name: string;

  @OneToMany(() => ChildEntity, child => child.parent)
  children: ChildEntity[];
}

import { Entity, PrimaryGeneratedColumn, Column, ManyToOne, JoinColumn } from 'typeorm';
import { ParentEntity } from './parent.entity';

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

  @Column()
  name: string;

  @ManyToOne(() => ParentEntity, parent => parent.children)
  @JoinColumn({ name: 'parentId' })
  parent: ParentEntity;
}