如何在实体中建立自我关系？

Question

我有实体文件：

@Entity('groups')
export class Groups {
  @PrimaryGeneratedColumn({ type: 'integer', name: 'id' })
  id: number;

  @Column({ type: 'int', nullable: true })
  parentid: number | null;

  @Column({ type: 'varchar', length: 1024 })
  name: string;

  @Column({ type: 'varchar', nullable: true, length: 4096 })
  description?: string;
}

并且我想成为父代的id是外键，就像这张图片一样：

也许有人知道我该怎么做？

感谢答案。

Answer 1

基于此link，有多种方法可以做到这一点，但我个人建议您这样做：

@Entity('groups')
export class Groups {
  @PrimaryGeneratedColumn({ type: 'integer', name: 'id' })
  id: number;

  @Column({ type: 'varchar', length: 1024 })
  name: string;

  @Column({ type: 'varchar', nullable: true, length: 4096 })
  description?: string;

  @Column({ nullable: true })
  parentId: number;

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

  @OneToMany((type) => Groups, (groups) => groups.parent)
  children: Groups[];
}