Question

我在更新具有多对多关联的实体时遇到问题，是否对我做错了事感到好奇，或者更具体地说，什么是正确的方法

请考虑以下实体...

@Entity
class Subject
  @PrimaryGeneratedColumn('uuid')
  id: string;

  @Column()
  name: string;

  @ManyToMany(() => Note, note => note.subjects)
  @JoinTable()
  notes: Note[];

  ...

@Entity()
export class Note {
  @PrimaryGeneratedColumn('uuid')
  id: string;

  @ManyToMany(() => Subject, (subject: Subject) => subject.notes)
  subjects: Subject[];

在我的代码中，我找到了该节点，然后尝试对其进行更新并保存，如下所示...

const note = await noteRepo.findOneOrFail(noteId);
const foundSubjects = await subjectRepo.findByIds(Array.from(subjectIds));
note.subjects = foundSubjects;
noteRepo.save(note);

但可惜，主题并没有保存在笔记上。

正确的方法是什么？

谢谢！

Answer 1

因此以下内容对我有用：

model <- keras_model_sequential() %>%
layer_dense(units = 16, activation = "relu", input_shape = c(1218)) %>%
layer_dense(units = 16, activation = "relu") %>%
layer_dense(units = 1, activation = "sigmoid")

model %>% compile(
optimizer = "rmsprop",
loss = "binary_crossentropy",
metrics = c("accuracy")
)

model %>% compile(
optimizer = optimizer_rmsprop(lr = 0.001),
loss = "binary_crossentropy",
metrics = c("accuracy")
)

model %>% compile(
optimizer = "rmsprop",
loss = "binary_crossentropy",
metrics = c("accuracy")
)

history <- model %>% fit(
x_train,
y_train,
epochs = 7,
batch_size = 500,
validation_data = list(x_test, y_test)
)

尽管如此，我仍然觉得repo.save（）方法应该有效

Answer 2

默认情况下，级联设置为false，您可以启用以下操作：

@Entity()
export class Note {
@PrimaryGeneratedColumn('uuid')
id: string;

@ManyToMany(() => Subject, (subject: Subject) => subject.notes, { cascade: true })
subjects: Subject[];

Answer 3

在我的情况下，我试图更新现有关系，但是由于该关系已经存在，这给我带来了独特的密钥冲突，因此我首先需要删除所有现有关系，然后添加更新的用户的关系：

export const updateUser = async (user: User): Promise<User | undefined> => {
    /**
     * Get the actual relationships of that user.
     */
    const actualRelationships = await getRepository(User)
        .createQueryBuilder()
        .relation(User, 'roles')
        .of(user).loadMany();

    /**
     * Add new relationships of the user, and delete the old relationships.
     */
    await getRepository(User)
        .createQueryBuilder()
        .relation(User, 'roles')
        .of(user)
        .addAndRemove(user.roles, actualRelationships);

    /**
     * Update only the table USER.
     */
    await getRepository(User)
        .createQueryBuilder()
        .update()
        .set({
            name: user.name,
            username: user.username,
            active: user.active
        })
        .where('id = :id', {id: user.id})
        .execute();

    /**
     * Return the updated user
     */
    return await getUser(user.id, true, true)
};

使用TypeORM更新多对多关系

3 个答案: