@OneToOne mapping delete then insert instead of updating-CodePudding

I've written some spring boot entities that have one-to-one relations inside. For example:

Student Entity

@OneToOne(cascade = CascadeType.ALL, orphanRemoval = true, fetch = FetchType.LAZY, mappedBy = "student")
private StudentClub studenttClub;

StudentClub Entity

@OneToOne(cascade = CascadeType.ALL, fetch = FetchType.LAZY)
@JoinColumn(name = "student_id", insertable = false, updatable = false)
private Student student;

When I try to update some student club information (i.e. club_code) by using .save of the Student repository, it deletes then inserts the updated data.

Hibernate: delete from student_club where club_code=? and student_id=?

Hibernate: insert into student_club (club_code, student_id) values (?,?)

Can we make it done by only 1 statement for example like

Hibernate: update ...

CodePudding user response：

.saveOrUpdate() method you can use it

-Calls either save() or update() on the basis of identifier exists or not. e.g if identifier exists, update() will be called or else save() will be called.

CodePudding user response：

Move @JoinColumn on StudentClub entity

@Entity
@Table(name = "STUDENT")
public class StudentEntity {
    @Id
    @SequenceGenerator(name = "StudentGen", sequenceName = "STUDENT_SEQ", allocationSize = 1)
    @GeneratedValue(generator = "StudentGen", strategy = GenerationType.SEQUENCE)
    @Column(name = "ID", unique = true)
    protected Long id;

    @OneToOne(fetch = FetchType.LAZY, cascade = {CascadeType.PERSIST, CascadeType.MERGE, CascadeType.REMOVE})
    @JoinColumn(name = "CLUB")
    public StudentClubEntity club;
}


@Entity
@Table(name = "STUDENT_CLUB")
public class StudentClubEntity {
    @Id
    @SequenceGenerator(name = "StudentClubGen", sequenceName = "STUDENT_CLUB_SEQ", allocationSize = 1)
    @GeneratedValue(generator = "StudentClubGen", strategy = GenerationType.SEQUENCE)
    @Column(name = "ID", unique = true)
    protected Long id;


    @Column(name = "NAME")
    public String name = "";

    @OneToOne(fetch = FetchType.LAZY)
    public StudentEntity student;
}

Try to test ...

@Test
public void test() {
    System.out.println("test");

    StudentEntity student = new StudentEntity();
    StudentClubEntity club = new StudentClubEntity();

    student.club = club;

    System.out.println("*****************************");
    student = studentRepository.saveAndFlush(student);

    student.club.name = "NEW NAME";
    student = studentRepository.saveAndFlush(student);

    System.out.println("*****************************");
}

Result

*****************************
Hibernate: call next value for student_seq
Hibernate: call next value for student_club_seq
Hibernate: insert into student_club (name, student_id, id) values (?, ?, ?)
Hibernate: insert into student (club, id) values (?, ?)
Hibernate: update student_club set name=?, student_id=? where id=?
*****************************