使用联接列单向一对多

Question

I've got the followings mappings (@OneToMany unidirectional). The fk is placed in IssueManagement and when I insert a new issuemanagement, two sql statements are executed (insert into IssueManagement and then update the fk) rather than just insert! I know that the fk is placed in owned table(IssueManagement) and the owner(Issue) is on the other side. Is there any workaround so that only one insert statement is executeD?

@Entity
@Table
public class Issue {
    @Id @GeneratedValue(strategy=GenerationType.IDENTITY)
    private Long id;

    @OneToMany(fetch=FetchType.EAGER, cascade={CascadeType.ALL})
    @JoinColumn(name="issue_id", nullable=false)
    List<IssueManagement> issueManagements= new ArrayList<IssueManagement>();

    public Long getId() {
        return id;
    }
    public void setId(Long id) {
        this.id = id;
    }
    public List<IssueManagement> getIssueManagements() {
        return issueManagements;
    }
    public void addIssueManagment(IssueManagment issueManagment) {
        issueManagements.add(issueManagment);
    }
}

and

@Entity
@Table
public class IssueManagement {
    @Id @GeneratedValue(strategy=GenerationType.IDENTITY)
    private Long id;

    public Long getId() {
        return id;
    }
    public void setId(Long id) {
        this.id = id;
    }
}

Answer 1

The solution is to add these arguments to the @JoinColumn

@JoinColumn(name = "parent_id", referencedColumnName = "id", nullable = false, insertable=false, updatable=false)

I still don't know why but this works! Much appreciated if anyone could explain why it works..