Question

我有2个实体（User，NewsItem），其ID之间存在多对多关系（AccessedBy）

这是用户实体：-

@Entity
@Table(name = "news_user")
public class User {

private UUID id;
private Set<AccessedBy> accessors = new HashSet<AccessedBy>();

@Id
@Column(name = "id")
public UUID getId() {
    return id;
}

public void setId(UUID id) {
    this.id = id;
}

@OneToMany(mappedBy = "user", cascade = {CascadeType.MERGE, CascadeType.DETACH}, orphanRemoval = true)
public Set<AccessedBy> getAccessors() {
    return accessors;
}

public void setAccessors(Set<AccessedBy> accessors) {
    this.accessors = accessors;
}
}

这里是新闻实体：-

@Entity
@Table(name = "news_item")
public class NewsItem {

private UUID id;
private Set<AccessedBy> accessors = new HashSet<>();

@Id
@Column(name = "id")
public UUID getId() {
    return id;
}

public void setId(UUID id) {
    this.id = id;
}

@OneToMany(mappedBy = "newsItem", cascade = {CascadeType.MERGE, CascadeType.DETACH}, orphanRemoval = true)
public Set<AccessedBy> getAccessors() {
    return accessors;
}

public void setAccessors(Set<AccessedBy> accessors) {
    this.accessors = accessors;
}
}

这是它们之间的关系（AccessedBy）：-

@Entity
@Table(name = "accessed_by")
@IdClass(AccessedById.class)
public class AccessedBy {

private User user;
private NewsItem newsItem;
private Boolean bookmarked;
private Boolean read;
private Boolean deleted;

@Id
@ManyToOne
@JoinColumn(name = "user_id", referencedColumnName = "id")
public User getUser() {
    return user;
}

public void setUser(User user) {
    this.user = user;
}

@Id
@ManyToOne
@JoinColumn(name = "news_id", referencedColumnName = "id")
public NewsItem getNewsItem() {
    return newsItem;
}

public void setNewsItem(NewsItem newsItem) {
    this.newsItem = newsItem;
}

@Column(name = "bookmarked", nullable = false)
public Boolean getBookmarked() {
    return bookmarked;
}

public void setBookmarked(Boolean bookmarked) {
    this.bookmarked = bookmarked;
}

@Column(name = "read", nullable = false)
public Boolean getRead() {
    return read;
}

public void setRead(Boolean read) {
    this.read = read;
}

@Column(name = "deleted", nullable = false)
public Boolean getDeleted() {
    return deleted;
}

public void setDeleted(Boolean deleted) {
    this.deleted = deleted;
}
}

假设用户要为新闻项添加书签。对于书签，我在AccessedBy表中输入一个书签属性设置为true的记录。而且我想从AccessedBy表中删除该记录，以防用户将其取消书签。我如何有效地做到这一点？

我尝试过的事情：-

我试图从两个实体的HashSet中删除我先前插入的AccessedBy对象，但是从调试中看不到该对象。

我想删除的方式：-

User user = checkUser(authorization);
    NewsItem newsItem = newsRepository.findByUniqueId(newsId);
    AccessedBy accessedBy = new AccessedBy(user, newsItem, true, false, false);
    user.getAccessors().remove(accessedBy);
   newsItem.getAccessors().remove(accessedBy);
    userRepository.saveAndFlush(user);
    newsRepository.saveAndFlush(newsItem);

checkuser（）检查基本身份验证并从数据库返回用户。

如何有效地从Spring Data jpa中带有多余列的联接表中删除？

0 个答案: