Hi all,

I am trying to figure out the mapping configuration for a map containing a set. The schema I would like is:

create table entity (id bigint not null, primary key (id));
create table key (id bigint not null, primary key (id));
create table entity_key_values (entity_id bigint not null, key_id bigint not null, value integer not null);

And the field in the entity that I want to map would be:



Note that in my case, I do not wish there to be a unique constraint on the entity_key_values table for the entity_id & key_id pair, as there should be multiple rows that will all have different values to be mapped into the Set.

I am using annotations, and I can map a simple Map<Key, Integer> to this schema, using:



But this (of course) this creates the entity_key_values join table with a primary key (unique) constraint on entity_id & key_id. And it doesn't work at all if I put the Set<> around Integer.

Any thoughts? If this isn't possible using annotations, is it possible using the xml configuration?

Also, if this mapping IS possible, can the value be a non-primitive type (eg. a Component or another Entity rather than a integer)?

I'm also wondering if this would be possible if the Set<V> was a field of a mapped entity - but then is it possible to have a collection field take it's values from multiple rows of the same table as the entity itself?

I'm also wondering if a mapping of map containing set would be possible if there was a second join table, as in:

create table entity (id bigint not null, primary key (id));
create table key (id bigint not null, primary key (id));
create table entity_key (id bigint not null, entity_id bigint not null, key_id bigint not null);
create table entity_key_value(entity_key_id bigint not null, value integer not null);

So the relationship between Entity and the entity_key join table would be one to many, and the join table to Key would be many to one, and then there would be a one to many relationship from the entity_key join table to the entity_key_value join table.

I've been doing a lot of searching though, and I'm beginning to think this might be a bit esoteric (although it seems pretty straight forward to me). Should it be a feature request?