It turns out I was doing it correct, I had just forgotten to save the database diagram that I had set the relationship (foreign key constraint) in.

Sorry to waste anybody's time.

>Hi,
>
>I've been trying to add some constraints to my database to ensure referential integrity. I've got cascading deletes to work, but now I'm trying to restrict a record being deleted if there is a related record in another table. How do I go about specifying this?
>
>Thanks,