Question

I have a 2 classes that share a UUID and are uni-directionally mapped. I use the UUID to group related rows, and this group shares many details (this is just an example):

@Entity @Table
class Something {
   @Id @Column("something_id")
   private Long id;

   private String uuid = UUID.randomUUID().toString();

   @OneToMany
   @JoinColumn("uuid")
   private List<Detail> details = new LinkedList<Detail>(); 
}

@Entity @Table
class Detail {
   @Id @Column("detail_id")
   private Long id;
   private String value;
   private String uuid;
}

I’m attempting to use Criteria:

Criteria c = getSession().createCriteria(Something.class).createAlias("details", "detail").add(Restrictions.eq("detail.value", someValue));

This is all fine and dandy, but I’m not getting results because of the join:

inner join DETAIL d1_ on this_.SOMETHING_ID=d1_.UUID 

Is it possible to specify:

inner join DETAIL d1 on this_.UUID=d1.UUID

I would have expected the join to use the @JoinColumn annotaiton to find the column to join on. I see that I can specify a join type, but I don’t see a way to specify the actual column.

Answer 1

I would have expected the join to use the @JoinColumn annotation to find the column to join on. I see that I can specify a join type, but I don’t see a way to specify the actual column.

The join is using the JoinColumn annotation since it’s joining on d1_.UUID. However, because you didn’t specify the referencedColumnName element, the foreign key is assumed to refer to the primary key of the referenced table (this_.SOMETHING_ID), hence the obtained result.

In other words, try this:

@OneToMany
@JoinColumn(name="uuid", referencedColumnName="uuid")
private List<Detail> details = new LinkedList<Detail>(); 

I’m not sure to understand the benefit but let’s say it’s another story.