I'm a little bit confused about how to map following situation.

i have one existing table for:

update
update_installation
application
database

d_App
d_sid
d_server

table application uses fixed values already stored in the (domain-) table d_App
table database uses fixed values already stored in the (domain-) table d_sid and d_server

One update can have multiple installations --> one-to-many

An installation must have (--> one-to-one or joined-subclass)

either one applikation (the name comes from the domain-data-table)
or
one database (contains one sid and one server from the domain-data-table)

What is the best way to map this situation?

I tried to do this with joined-subclasses form installation to applikation and database, but i always get exception like in my last post.

Maybe i could use component-mapping but i didn't see how to put a component into it's own table in the database.

Any help and ideas would be very welcome!