Hi,

Can someone tell me why a unidirectional one-to-many association on a foreign key is not recommendated?

It is stated so in the hibernated manual, chapter 8. It is also stated that a unidirectional one-to-many association on a join table is much preferred.

The recommended method approach requires maintaining an extra table, which is I find is counter intiutive.

Is there any writup this?

Many thanks in advance,

regards,
Yee

Hi,

Using unidirectional one-to-many (inverse=false) first saves the child (with null in foreign key column) and then updates it to create the association.
Using inverse=true NH does nothing even if one-to-many collection is dirty, so you need the other side of the association (many-to-one) to create the link, but the benefit is that the FK value is never null (especially if used with cascade=all-delete-orphan)

In my opinon instead of messy workarounds with link-table it is much better to use inverse=true.

I see - hibernate manual is a bit misleading on this. The recommendation should really be that one should stick to bidirectional associations (inverse = true), rather than saying that using join table is much preferred.

Thanks.

Yee

I believe the manual you read was for Hibernate 3, not for 2.1.

Yes - it was downloaded on Oct 4, 2005 - hibernate Reference Documentation V3.0.5