I have two tables Employee and Contact. Actually Employee table is extended to Contact. Some of the fields of both tables:

Employee
(
EmployeeID (PK)
ContactID (FK)
Title
BirthDate
...
)

Contact
(
ContactID (PK)
FirstName
LastName

)

Could I use joined-class to map those two classes? I like to declare inheritance between those two classes

Thanks!

You can use joined-subclass, but the primary key in the Employee Table would be the ContactId (since that *is* the key for a subclassed Contact).

An alternative would be to use Decorator for Employee and delegate references to an inner Contact...I usually encourage that before subclassing unnecessarily.