@OrderColumn, @OneToMany & null index column for collection

Question

I am trying to create parent child tables where the order is preserved. The example 7.8 from Hibernate documentation shows how to do this:

@Entity
public cl         


        

Answer 1

Do something like this:

@Entity
class Parent {

    @OneToMany
    @IndexColumn(name = "index_column")
    List children;
}

@Entity
class Child {

    @ManyToOne
    Parent parent;
    @Column(name = "index_column")
    Integer index;

    @PrePersist
    @PreUpdate
    private void prepareIndex() {
        if (parent != null) {
            index = parent.children.indexOf(this);
        }
    }
}