Hehe too fast, I meant option 3. :D
Mit freundlichen Grüßen, ------------------------------------------------------------------------ *Christian Beikov* Am 03.05.2017 um 16:01 schrieb Steve Ebersole: > To circle back to this... I mentioned possibly keeping a reference to > the foreign-key defining the join predicate between the root table and > the secondary table. ATM however we do not model FKs in the runtime > metamodel (either in 6 or before). So that will not work unless we > start to do that. > > Another possibility is to simply keep the list of columns from the > secondary table that are used in the join predicate. This would work > because of an explicit rule followed by both Hibernate and JPA - > namely that secondary tables (and joined inheritance tables btw) join > back to the PK columns of the root table. In other words, we > implicitly know the "left hand side" portion of the join predicate. > > So we have 3 options total for modeling this join predicate: > > 1. Maintain a predicate tree as part of this SecondaryTableBinding. > ATM we have no such concept of this either in the runtime > metamodel, so we would need to add this if we choose this option. > This would mean adding the concept of conjunction/disjunction and > relational-operators in some form to the runtime metamodel. > Personally, this is my least favorite option. > 2. Maintain the join predicate on SecondaryTableBinding via a FK > reference. Again, this would mean adding a new concept/class to > model the FK as part of the runtime metamodel. I am not against > this option so long as we deem it has similar benefits in other > parts of the codebase - I'd prefer to not add such a concept just > to handle this case. > 3. Follow the assumption regarding the "left hand side" of these > joins and just keep a list of the columns from the secondary table > that link to the entity's root table's PK columns. > > > FWIW, both Hibernate and JPA also assume that the same holds true for > joined inheritance tables. Whatever we decide here for secondary > tables, we should apply to modeling joined inheritence for consistency > - perhaps even to the point of a shared contract (NonRootTableBinding?). > > Opinions? > > On Wed, Apr 19, 2017 at 8:35 AM Steve Ebersole <st...@hibernate.org > <mailto:st...@hibernate.org>> wrote: > > On Wed, Apr 19, 2017 at 6:00 AM Christian Beikov > <christian.bei...@gmail.com <mailto:christian.bei...@gmail.com>> > wrote: > > Sounds good. I hope the secondary table stuff is getting > defined on a > higher level(EntityPersister/AbstractEntityPersister). I had > problems > implementing OneToOne-JoinTable support for > TablePerClass(UnionSubclassPersister) a while ago and I guess > that was > because there is no notion of secondary tables in the > EntityPersister. I > guess that issue would be solved then? :) > > > Not sure what you mean by "higher level". The design here > specifically shows secondary tables modeled as top-level concepts > (SecondaryTableBinding). So I think, again iiuc, that the design > already shows secondary tables "defined on a higher level". > _______________________________________________ hibernate-dev mailing list hibernate-dev@lists.jboss.org https://lists.jboss.org/mailman/listinfo/hibernate-dev
