Hi,

I actually use Hibernate 1.2.5
The data I have to exploit in hibernate powered applications are set on several databases.
eg (with manytoone associations):

GrantClass ===>user===> UserClass
ReportClass ===>user===>UserClass

GrantClass is mapped on tbl_grants on database A
UserClass is mapped on tbl_users on database A
ReportClass is mapped on tbl_reports on database B

Actually, to solve this kind of graph I declare 2 JNDI session factories.

In Session Factory A, GrantClass and UserClass are joined by many-to-one and one-to-many hibernate properties ==> Very useful.
In Session Factory B, I declare a "long" property on the ReportClass mapping to join with the tbl_users table ==> not useful at all.

So an example of code exploiting these classes is :

Session sA = sfA.openSession();
Session sB = sfB.openSession();

UserClass u = (User)sA.load(UserClass.class, new Long(1234));
u.initialize(sB);
//in UserClass : public void initialize(Session s) {
// set reports = s.find("from r in class ReportClass where r.userId = "+this.getKey())
//



Is there a smarter way to build objects graphs with data on several datasources. I didn't find such a solution in Hibernate 1.2.x. Does Hibernate 2.x does it ?

For example, I would like to declare in some manner in User mapping a one-to-many java Set using an other session.

Sorry if it isn't very clear (my english isn't fluent !)

Thanks

No Hibernate does not do mapping over mutliple databases, not in 2.1.2 too.

IIRC, there was some mention in the past about writing a custom UserType to do it. I don't know the details though - I have never tried it.

Also, what database are you using? Some databases allow cross db joins, which would allow you to map all classes in a single SessionFactory by using the schema attribute of the class mapping (I do this in SQL Server 2000, for example).

Note that a solution at the database level is much better. Most DBMW have some kind of database links, so this is only an issue in a heterogenous setup.