前端 - nestjs+typeorm,多对多关系，删除报错？

Question

文章实体

import {
  Column,
  Entity,
  JoinTable,
  ManyToMany,
  PrimaryGeneratedColumn,
} from 'typeorm';
import { Tag } from './tag.mysql.entity';

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

  @Column({
    length: 100,
    comment: '文章标题',
  })
  title: string;

  @Column({
    type: 'text',
    comment: '文章内容',
  })
  content: string;

  @JoinTable()
  @ManyToMany(() => Tag, (tag) => tag.articles)
  tags: Tag[];
}

标签实体

import {
  Column,
  Entity,
  JoinTable,
  ManyToMany,
  PrimaryGeneratedColumn,
} from 'typeorm';
import { Article } from './article..mysql.entity';

@Entity()
export class Tag {
  @PrimaryGeneratedColumn()
  id: number;
  @Column({
    length: 50,
    comment: '标签名',
  })
  name: string;

  @ManyToMany(() => Article, (article) => article.tags)
  articles: Article[];
}

然后我测试新增，随便添加几条数据

// 测试多对多的关系 新增
  async textManytoMany() {
    const t1 = new Tag();
    t1.name = '测试标签1_' + this.random();

    const t2 = new Tag();
    t2.name = '测试标签2_' + this.random();
    const t3 = new Tag();
    t3.name = '测试标签3_' + this.random();
    const a1 = new Article();
    a1.title = '测试文章1_' + this.random();
    a1.content = '测试文章1_' + this.random();
    a1.tags = [t1, t2, t3];
    const a2 = new Article();
    a2.title = '测试文章2_' + this.random();
    a2.content = '测试文章2_' + this.random();
    a2.tags = [t1, t2, t3];
    const a3 = new Article();
    a3.title = '测试文章3_' + this.random();
    a3.content = '测试文章3_' + this.random();
    a3.tags = [t1, t2, t3];
    await this.tagRepository.save([t1, t2, t3]);
    await this.articleRepository.save([a1, a2, a3]);
    return {
      t1,
      t2,
      t3,
      a1,
      a2,
      a3,
    };
  }

查询文章id=1

查询标签id=6

删除文章没问题

但是，删除标签id=6就报错了。服务器错误

  // 测试多对多的关系 查询文章
  async findArticle(id: number) {
    const article = await this.articleRepository.findOne({
      where: { id },
      relations: ['tags'], // 这里的 tags 是 article.entity.ts 中的 tags 字段 @ManyToMany(() => Tag)
    });
    return article;
  }

  // 测试多对多的关系 查询标签
  async findTag(id: number) {
    const tag = await this.tagRepository.findOne({
      where: { id },
      relations: ['articles'], // 这里的 articles 是 tag.entity.ts 中的 articles 字段 @ManyToMany(() => Article)
    });
    return tag;
  }

  // 测试多对多的关系 删除文章
  async deleteArticle(id: number) {
    return this.articleRepository.delete(id);
  }

  // 测试多对多的关系 删除标签
  async deleteTag(id: number) {
    return this.tagRepository.delete(id);
  }

query failed: DELETE FROM `tag` WHERE `id` IN (?) -- PARAMETERS: [6]
error: Error: Cannot delete or update a parent row: a foreign key constraint fails (`typeorm_test`.`article_tags_tag`, CONSTRAINT `FK_5fee2a10f8d6688bd2f2c50f15e` FOREIGN KEY (`tagId`) REFERENCES `tag` (`id`) ON DELETE NO ACTION ON UPDATE NO ACTION)

Answer 1

article没有写manytomany映射关系