Implementing a “Both, Either-or, but Not Null” Requirement in a Database

Question

I have requirement for a web app that states that a user should be able to either upload an instruction document(s) (.pdf, .doc, .txt) or provide text for the instructions. The

Answer 1

Something feels a bit off here

1. There is no UserID in this schema, so it should be added to the Instruction table.

2. If a user does not upload anything, there will (should) be no entry for that user in the Instruction table.

3. So the problem -- as stated -- is not about placing constraints on these three tables.

4. When loading this structure, use a stored procedure and/or a transaction -- to make sure that at least one of the child record gets populated. Though, this has nothing to do with the business requirement that user has to upload something.