Hibernate - Foreign keys instead of Entities

Question

Currently, Hibernate allows me to load objects defined by *-to-one relationships directly with

entity1.getEntity2() 

Is it possible to get the foreign key instead of the object?

The current approach which I see is having addint to my mapping:

@JoinColumn(name="message_key") @ManyToOne(targetEntity=Message.class,fetch=FetchType.LAZY) private Message message;  //these lines currently exist  @Column(name="message_key") private Long message_fk; //the idea is to add those 2 lines 

Is there a better approach to get the foreign key, or is this the only one?

Answer 1

Yes, you can do that. You just need to make it clear for hibernate which one is the mapping that it's supposed to maintain, like so:

@Column(name="message_key", updatable=false, insertable=false) private Long message_fk; 

Answer 2

If you still want a reference to your entity but don't want to load it from the database just to get the foreign key, your approach is the correct one. Add insertable and updatabale = false to the Column attribute to prevent losing the correct reference to an entity.

@JoinColumn(name = "message_key") @ManyToOne(targetEntity = Messages.class, fetch = FetchType.LAZY) private Messages message;  @Column(name = "message_key", insertable = false, updatable = false) private Long message_fk;