I've a DB table called MYTABLE with the following columns:

| Prim. Key | X | Y | z |
-------------------------
|...................|....|.....|....|

I've a domain named CHILDOFMYOBJECT which can be mapped on MYTABLE.
I've a domain object named MYOBJECT whose primary key is X + Y. Unfortunately
there is not a table in which X + Y is the primary key.
How can I map MYOBJECT? Sholud I create a view of MYTABLE (with distinct X,Y) and use it to map MYOBJECT?
Does this solution generate problems?