How to get access to a JoinColumn from a JSON result?

Ryggl

I only can get the related object in my Datatables but not the column I set in the @JoinColumn annotation in my model object:

@Column(name = "comment")
private String comment;
@JoinColumn(name = "orderID", referencedColumnName = "orderID", insertable = true)
private Order order;

To get the comment column I need to set "comment" for my aaData variables. But what do I set for the orderID of the related Entity? I don't want to get the object. I'm totally new in hibernate and Datatables so I don't know if you can understand my question or if this is a very dumb question. But maybe there is anybody who can help me and know what I mean. :-)