After some investigation it looks like the path of least resistance is
to just use SQL Alter Table to add the foreign keys with delete cascade
(I'm using forward mapping to create the database). It is not clear to
me how to use the @ForeignKey annotation with a ManyToMany relation
(possibly requires using the ContainerTable annotation also?). I also
tried setting the MappingDefaults property ForeignKeyDeleteAction value
but this added foreign keys on all the OneToMany and OneToOne relations
and changed the generated SQL forward mapping in other ways. At this
point the annotations seem less user friendly than SQL alter table.
As far as I can tell the only JPA "standard" way to do this is to remove
the elements one at a time from the owner side collection of the
ManyToMany relation before removing the owner entity.
- Paul
On 4/3/2009 11:38 AM, Paul Copeland wrote:
Looks like I can use the OpenJPA @ForeignKey annotation
deleteAction=CASCADE - will give it a try.
On 4/3/2009 11:18 AM, Paul Copeland wrote:
This is from the JPA spec - Sounds like cascade=REMOVE should not be
used on ManyToMany. However I'm recalling that some databases do
provide DDL for the kind of cascade delete behavior that I want.
2.1.7 - "The relationship modeling annotation constrains the use of
the cascade=REMOVE specification. The
cascade=REMOVE specification should only be applied to associations
that are specified as One-
ToOne or OneToMany. Applications that apply cascade=REMOVE to other
associations are not portable."
On 4/3/2009 10:43 AM, Paul Copeland wrote:
Will CascadeType.REMOVE on a ManyToMany mapping remove the join
table row? Even if the Collections has not been loaded lazily? Or
do I have to iterate over the Collection and remove each element
before removing the enity? I do NOT want to remove the referenced
Entity on the other side of the ManyToMany association, just the row
in the join table.
@ManyToMany (fetch=FetchType.LAZY,
cascade={CascadeType.PERSIST,CascadeType.REMOVE})
- Paul
