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Accepted
Timofey Melentev
Asked:2022-05-25 18:44:25 +0000 UTC2022-05-25 18:44:25 +0000 UTC

多对多关系的查询有什么问题？

  • 772

我想实现多对多连接（我使用 type-graphql、graphql、typeorm），我需要创建一个游戏，同时将它放在玩家的游戏数组中：

@ObjectType()
@Entity()
export class User extends BaseEntity {
  ...

  @ManyToMany(() => Game, game => game.players, { cascade: true }) @JoinTable()
  games: Game[];
}

@ObjectType()
@Entity()
export class Game extends BaseEntity {
  
  // От этих p1id и p2id хочу отказаться, чтобы можно было ссылаться на связь с User
  @Field(() => Int, {nullable: false})
  @Column()
  p1id: number;

  @Field(() => Int, {nullable: true, defaultValue: 0})
  @Column({nullable: true, default: 0})
  p2id: number;

  ...

  @ManyToMany(() => User, user => user.games)
  players: User[]  
}

为此，解析器中有以下功能：

  @Mutation(() => Game)
  async createGame(@Ctx() { req }: MyContext) {
    const initialWord = await generateRandomWord();
    const currUser = await User.findOne({ id: req.session.userId });

    if (currUser) {
      let userGames = [];
      if (currUser.games !== undefined) {
        currUser.games.map((i) => userGames.push(i));
      }      
      const game = await getConnection()
        .createQueryBuilder()
        .insert()
        .into(Game)
        .values({
          status: false,
          initialWord,
          p1id: req.session.userId,
        })
        .returning("*")
        .execute();
      const res = game.raw[0] as Game;
      userGames.push(res);                
      await getConnection()
      .createQueryBuilder()
      .update(User)
      .set({games: userGames as Game[]})
      .where("id = :id", {id: req.session.userId})
      .execute();      
      return game.raw[0] as Game;
    }
    throw new UnauthorizedError();
  }

我不明白为什么它在被问到时显示以下内容：

query failed: UPDATE "user" SET "userId" = $1, "updatedAt" = CURRENT_TIMESTAMP WHERE "id" = $2 -- PARAMETERS: [null,1]
[0] error: error: столбец "userId" в таблице "user" не существует

这个 userId 在请求中来自哪里？为什么它没有更新您需要的内容？

javascript

1 个回答

  1. Best Answer

    此处未更新，很可能是由于使用.set. 应该用过.add。

    .d.ts 说：

    /**
 * Adds (binds) given value to entity relation.
 * Value can be entity, entity id or entity id map (if entity has composite ids).
 * Value also can be array of entities, array of entity ids or array of entity id maps (if entity has composite ids).
 * Works only for many-to-many and one-to-many relations.
 * For many-to-one and one-to-one use #set method instead.
 */
add(value: any | any[]): Promise<void>;

    这是工作代码：

    import 'reflect-metadata';
import {
  createConnection,
  Entity,
  getRepository,
  PrimaryGeneratedColumn,
  BaseEntity,
  ManyToMany,
  JoinTable
} from 'typeorm';

@Entity()
class User1 extends BaseEntity {
  @PrimaryGeneratedColumn('increment')
  id: number;

  @ManyToMany(() => Game1, (game) => game.players, { cascade: true })
  @JoinTable()
  games?: Game1[];
}

@Entity()
class Game1 extends BaseEntity {
  @PrimaryGeneratedColumn('increment')
  id: number;

  @ManyToMany(() => User1, (user) => user.games)
  players?: User1[];
}

(async () => {
  const connection = await createConnection({
    type: 'postgres',
    username: process.env.POSTGRES_LOCAL_DBUSER,
    database: 'test',
    synchronize: true,
    logging: true,
    entities: [
      User1, Game1
    ]
  });

  try {
    const game1 = await getRepository(Game1).save({});
    const user = await getRepository(User1).save({ games: [game1] });

    const game2 = await getRepository(Game1).save({});
    user.games = [ ...user.games, game2 ];
    await getRepository(User1).save(user);

    const game3 = await getRepository(Game1).save({});
    await getRepository(User1)
      .createQueryBuilder()
      .relation(User1, 'games')
      .of(user)
      .add([ game3 ]);

    const item = await getRepository(User1).findOne(user.id, { relations: ['games']});
    console.log(item);
    
  } catch (err) {
    console.error(err);
  }

  await connection.close();

})();

    User1 {
  id: 15,
  games: [ Game1 { id: 1 }, Game1 { id: 2 }, Game1 { id: 3 } ]
}

    顺便说一句，您不需要在代码中使用 QueryBuilder，.find-ov 和.save. 我在一个例子中展示了它们的用法。

    node.js v16.2.0，typescript v4.2.3，typeorm v0.2.32

    • 1

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