Re: [eclipselink-users] JPA 2 @OrderColumn question

[James Sutherland <jamesssss@xxxxxxxxx>]

Set, and HashSet are not ordered.  These collection types have no order in
Java, so I'm not sure what expect???

If you want order, you need to use a List in Java.  Lists are generally more
usable collection types.
You can add a constraint to your join table to enforce no duplicates.


NBW wrote:
> 
> 
> I was reading over the docs [1] regarding Eclipselink's support for
> @OrderColumn. It looks like this only applies to List and not Set. The
> reason I ask is because I have a ManyToMany bi-directional relationship
> (using a join table) which is a Set and is implemented with a HashSet
> because the collection can't have duplicates.  
> 
> I wanted to order the entries in this set using @OrderColumn, but it
> appears I can only apply this to List, however using List will break my
> unique requirement.  Is this understanding correct?
> 
> If so what is the recommended strategy for this case?
> 
> Thanks,
> 
> -Noah
> 
> [1] - http://wiki.eclipse.org/EclipseLink/Examples/JPA/2.0/OrderColumns
> 
> 
> 


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