Foreign Key column mapped to multiple primary keys

Question

I have a database which has three tables

Messages - PK = MessageId
Drafts - PK = DraftId
History - FK = RelatedItemId

The History table has a sin

Answer 1

In a short description the solution you have used is called:
Polymorphic Association
Objective: Reference Multiple Parents
Resulting anti-pattern: Use dual-purpose foreign key, violating first normal form (atomic issue), loosing referential integrity
Solution: Simplify the Relationship

More information about the problem.

BTW createing a common super-table will help you: