I get this failure by mapping a OneToOne-Relationship:
The ProductID of table Product is a composite key which has the SAME Columns than the composite key ItemID in table Item:
This HQL works and returns the item-instance of a product:
This HQL does not work and returns the exception:
Instead of JoinColumn, I have tried it with PrimaryKeyJoinColumns (the same exception occurs):
(Another point is, when I annotate the @OneToOne above the getter instead above the field, then Hibernate totally ignores my OneToOne-Mapping and recognices the Item-Instance (or Product-Instance) as a column instead of a relationship, hence it produces false sql-selects)
I have also tried to use the PrimaryKeyJoinColumns-Relation in Class Product:
and delete the relation in Class Item (to make the oneToOne at least unidirectional):
Doing that HQL:
returns the same failure:
Do I have to use Hibernates ForeignGenerator within my Item-Class (I have a composite key!) ?:
Please, can you say me: What is wrong with my mapping?
It is really hard to believe that such a OneToOne-Mapping with a composite key is so hard to implement by using ORM (Hibernate).
Such relationships are very common.
This one time, at bandcamp, I had relations with a tiny ad.