Question

I was just reading the Hibernate documentation and came across the warning on this page

http://docs.jboss.org/hibernate/annotations/3.5/reference/en/html_single/#d0e1150

“Warning
The Hibernate team has always felt such a construct as fundamentally wrong. Try hard to fix your data model before using this feature.” with regards to Partial identifier generation

Can someone explain to me in a little more detail what is actually wrong with this? Why does Hibernate look down on generated values? Does that include auto incremented values in Hibernate?

Thanks,

Answer 1

The warning is not about using @GeneratedValue on a class that has only one id field.
The warning is about using @GeneratedValue in one column of a composite key, which is a very odd use case (never seen a need for something like this in 12 years).

So the warning is: If you need to use @GeneratedValue in a composite key, then review your model, because there’s a big chance that there’s something wrong with it.

If you think that this doesn’t answer your question, can you provide an example where you might need this feature?