Good morning everyone,

I'm experincing a problem with hibernate and many-to-many relations. I have the following situation:


And I have this hibernate mapped XML:

Usuario.hbm.xml



EventoAgenda.hbm.xml



The class Usuario.java, have a collection of EventoAgenda and EventoAgenda have a collection of Usuario. This is a bidirectional relationship between this two tables. This relationship has a table named USU_EAG that makes the association of this two tables. This table has only two fields tha represents the primary key of Usuario and EventoAgenda.

Problem: The problem is that when I insert a new EventoAgenda in Usuario and makes the UPDATE/INSERT, the hibernate removes all registries in the table, for that user, and insert again wih the new one. This is causing a huge problem of performance. Can anyone help me?

Thanks.

The problem may be in the implementation of the getter/setter of the collections. Are you returning the same instance from the Usario.getEventosAgenda() as Hibernate passes to Usario.setEventosAgenda(). If not you will get the behavior as you describe.

By the way... Are the <idbag> mappings really working? I have no experience using <idbag>:s, but I think it seems a bit strange that you have four columns in the USU_EAG table, but each <idbag> only uses three of them. Shouldn't the column use in a <many-to-many> on one side match the <key> column of the other side? Shouldn't one of the sides be mapped with inverse="true"?