I have article table and several user tables a_user, b_user, ... with exactly the same structure (but different data). I can't change anything in *_user tables except their table name prefix but can change everything else (user tables contain only user information, there is nothing about article or user_type in them).

I need to link article to a user (many-to-one), but user table name is defined by user_type field. For example

Article table record:
...
user_id="5"
user_type="a"

means that it is linked to a user with id=5 from a_user table (id 5 is not unique in users scope, each user table can have its id 5).

Any suggestions how to handle this situation? How can I map this relation in Hibernate (xml mapping, no annotations) so it will automatically pick up correct user for an article during select/update? How should I map user tables (one or multiple classes?)?

I would need to run some queries like this:

from Article a where a.userType=:type and a.user.name=:name

Thanks.