java - 具有ManyToMany关系的级联删除

Question

这个问题已经有答案了:

How to remove entity with ManyToMany relationship in JPA (and corresponding join table rows)? (10 个回答)

已关闭 7 年前。

我有以下实体。我希望能够删除用户，并且 UserGroupMap 中包含该用户的任何条目也应该被删除。但是，每次我尝试删除在 UserGroupMap 中也有条目的用户时，都会收到以下错误。无法删除或更新父行:外键约束失败如何实现此行为？ p>

@Entity
public class User {

   @Id
   private Long id;

   @Column
   private String name;

   @ManyToMany(mappedBy = "users", cascade = CascadeType.All)
   private Set<Group> groups;

 }


@Entity
public class Group {

   @Id
   private Long id;

   @Column
   private String type;

    @ManyToMany
    @JoinTable(name = "UserGroupMap", 
            joinColumns = @JoinColumn(name = "groupId", referencedColumnName = "id"), 
            inverseJoinColumns = @JoinColumn(name = "userId", referencedColumnName = "id") )
   private Set<User> users;

 }

Answer 1

您应该将 (cascade=CascadeType.REMOVE) 添加到您的多对多关系

喜欢这个例子

@ManyToMany(cascade=CascadeType.REMOVE)