[SOLVED] ERROR: update or delete on table "tablename" violates foreign key constraint

ERROR: update or delete on table "tablename" violates foreign key constraint

I'm trying to delete the parent student or parent course and I get this error:

Caused by: org.postgresql.util.PSQLException: ERROR: update or delete on table "student" violates foreign key constraint "fkeyvuofq5vwdylcf78jar3mxol" on table "registration"

RegistrationId class is a composite key used in Registration class. I'm using Spring data jpa and spring boot.

What am I doing wrong? I know that putting cascadetype.all should also remove the children when the parent is deleted but it is giving me an error instead.

@Embeddable
public class RegistrationId implements Serializable {

  @JsonIgnoreProperties("notifications")
  @OneToOne(cascade=CascadeType.ALL)
  @JoinColumn(name = "student_pcn", referencedColumnName="pcn")
  private Student student;

  @JsonIgnoreProperties({"teachers", "states", "reviews"})
  @OneToOne(cascade=CascadeType.ALL)
  @JoinColumn(name = "course_code", referencedColumnName="code")
  private Course course;

Registration class

@Entity(name = "Registration")
@Table(name = "registration")
public class Registration {

@EmbeddedId
private RegistrationId id;

Solution

I made it work by using hibernate @OnDelete annotation. Some how the JPA.persistence CascadeTypes were not working. They had no effect for whichever I chose.

Just like below. Now I can remove the parent Student or the parent Course and all children(Registrations) are deleted with them.

@Embeddable
public class RegistrationId implements Serializable {

    @JsonIgnoreProperties("notifications")
    @OnDelete(action = OnDeleteAction.CASCADE)
    @OneToOne
    @JoinColumn(name = "student_pcn", referencedColumnName="pcn")
    private Student student;

    @JsonIgnoreProperties({"teachers", "states", "reviews"})
    @OnDelete(action = OnDeleteAction.CASCADE)
    @OneToOne
    @JoinColumn(name = "course_code", referencedColumnName="code")
    private Course course;