@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

The bug refers to Hibernate 3.5.3 while documentation refers to Hibernate 3.6. It is my understanding from comments that the issue HHH-5390 has been resolved. Which version of Hibernate do you use? Note that you must have a column with exact specified name in @OrderCoulumn.

Also see this discussion about that same issue and a workaround in case of 3.5.

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Update

Apparently it remains unsupported and there is a documentation bug as described by HHH-5732. I thought from HHH-5390 that the person who it was assigned (same who owns HHH-5390) has agreed to fix it. But it's not clear whether and when it is going to happen.

Answer 2

Do something like this:

@Entity
class Parent {

    @OneToMany
    @IndexColumn(name = "index_column")
    List<Child> 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);
        }
    }
}

Answer 3

Maybe these can help you:

I have the same problem with an old version of hibernate (3.5.6) with tag @IndexColumn and find one good non-invasive workaround: try to change your List<Message> to Set<Message> Object and use HashSet instead of ArrayList. It's seems that old Hibernate versions work better with Sets.

Good luck!

Answer 4

For me the point was to set the column declared in @OrderColumn to the NOT NULL and with default value 0

Answer 5

Moin,

the same problem occurs on hibernate.core 5.1.4 final. Using Set and HashSet on tag @OrderColumn (like Augustin said) fix the problem.