Common example is the Customers table with a SalePeople subclass table that both use the EmployeeID as their primary key)<BR><BR>When I make a foreign key reference to these tables in other tables ...

Foreign key 'geneassay_fk' references invalid column 'geneassay' in referencing table 'b_SequencingData_seq'. Msg 1750, Level 16, State 0, Line 43 Could not create constraint.