matveykkk's questions

我需要删除 User'a，但由于他有连接（订阅和订阅者），对象没有被删除，我该如何正确实现呢？

抛出的异常：

Cannot delete or update a parent row: a foreign key constraint fails (`sweater_db`.`sweater_user_subscribers`, CONSTRAINT `user_role_subscribers_subscriber_fk` FOREIGN KEY (`subscriber_id`) REFERENCES `sweater_user` (`id`))

用户

@Entity
@Table(name = "sweater_user")
public class User implements UserDetails{

    private final static long serialVersionUID = 1L;

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    @NotBlank(message = "Username should not be empty")
    private String username;

    @NotBlank(message = "Password should not be empty")
    private String password;

    @Email(message = "Email is not correct")
    @NotBlank(message = "Email should not be empty")
    private String email;

    private String activationCode;

    private boolean active;

    @ManyToMany(cascade = CascadeType.ALL, fetch = FetchType.EAGER)
    @JoinTable(
            name = "sweater_user_role",
            joinColumns = @JoinColumn(name = "user_id", referencedColumnName = "id"),
            inverseJoinColumns = @JoinColumn(name = "role_id", referencedColumnName = "id")
    )
    private Collection<Role> roles;

    @OneToMany(mappedBy = "author", cascade = CascadeType.ALL, fetch = FetchType.LAZY)
    private Collection<Message> messages;

    @ManyToMany(fetch = FetchType.EAGER)
    @JoinTable(
            name = "sweater_user_subscribers",
            joinColumns = @JoinColumn(name = "channel_id"),
            inverseJoinColumns = @JoinColumn(name = "subscriber_id")
    )
    private Set<User> subscribers = new HashSet<>();

    @ManyToMany(fetch = FetchType.EAGER)
    @JoinTable(
            name = "sweater_user_subscriptions",
            joinColumns = @JoinColumn(name = "subscriber_id"),
            inverseJoinColumns = @JoinColumn(name = "channel_id")
    )
    private Set<User> subscriptions = new HashSet<>();