Yeah, long story short, if I have the same columns in both tables (and thus the same fields for the Record key are in both Java entities), it works no problem.
>From what I gather in my googling of the problem, this is basically a limitation of JPA 1.0: if you want to do a relationship on a value that is part of a composite key, ALL key fields must be present in both classes. They don't need to actually be @Id fields in both classes... just present to use in the join logic. So the solution was to add owner and source to the RecordDetails table... not a big deal but seems weird JPA required that. But then I didn't design the schema and am by no means a DB expert so perhaps that should have been the DB design from the beginning. On Fri, Jul 2, 2010 at 8:23 AM, Josh Peters <jcpet...@gmail.com> wrote: > I found this article by IBM to be helpful for understanding Hibernate > + JPA and composite keys: > http://www.ibm.com/developerworks/opensource/library/os-hibernatejpa/index.html > > Short story: you'll have to extract your composite key into its own > class and then use that as the @Id field. > > Good luck. > > On Jul 1, 3:20 pm, Sean Comerford <sean.c.comerf...@gmail.com> wrote: > > Hours of googling have failed so I'm hoping one of you JavaPosse list > > geniuses can bail me out here :-) > > > > I have what I think is a pretty simple relationship between two DB > tables. > > > > Record > > --------- > > int seqId (key) > > int owner (key) > > String source (key) > > ... other non key fields ... > > > > RecordDetails > > ------------------- > > int genId (key) > > int seqId > > String detailsText > > > > So record has a one to many relationship with record details based on the > > seqID. > > > > The catch here is the primary key in the record table is COMPOSITE > > consisting of seqId, owner and source (whereas RecordDetails pk is just > the > > generated column genId). > > > > Starting with just having: > > > > @OneToMany > > @JoinColumn(name="seqId") > > private List<RecordDetails> details ... > > > > I've tried 18 different ways to model this in JPA / Hibernate and after > much > > googling still can't get it to work. > > > > The jist of my googling seems to be that there's a limitation in JPA 1.0 > in > > that ManyToOne and OneToMany relationships on foreign keys MUST have the > > same key columns. > > > > My gut feeling is there MUST be a way around this... I'm willing to use > > Hibernate annotations if necessary. > > > > Can anyone help me out? > > -- > You received this message because you are subscribed to the Google Groups > "The Java Posse" group. > To post to this group, send email to javapo...@googlegroups.com. > To unsubscribe from this group, send email to > javaposse+unsubscr...@googlegroups.com<javaposse%2bunsubscr...@googlegroups.com> > . > For more options, visit this group at > http://groups.google.com/group/javaposse?hl=en. > > -- You received this message because you are subscribed to the Google Groups "The Java Posse" group. To post to this group, send email to javapo...@googlegroups.com. To unsubscribe from this group, send email to javaposse+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/javaposse?hl=en.
