>Hi,
>
>I've got a SQL Server Express 2008 R2 database which has a Person table where I store People and their dependents like this:
>
>PersonId
>Name
>ParentId
>
>So one PersonID can have many dependents by storing their ID in the ParentID field (simple self join).
>
>I want to set up referential Integrity on this table so that if a parent is deleted, their dependents are deleted (cascade). I created a database diagram, dropped my Person table on it and then dragged the PersonId field to the ParentID field. However, when I try to set the Delete Rule to Cascade, it is disabled.
>
>How can I do this?\

I don't believe such complex RI is supported. Most likely you need to implement this RI through the trigger.