Best method to verify multi-level relational dependencies

Question

Suppose you have entities A, B, C and D.

• D relates to C
• C relates to B
• B relates to A

Furthermore, user is only allowed to <

Answer 1

The obvious solution would be this: Given D, find C, then find B and eventually find A. If the chain breaks somewhere, access to D would be rejected. Unfortunately, this requires - if trivially implemented - 4 database accesses instead of just the one for A.

I suppose that might be possible. It depends in part on what "relates to" means, but assuming a relatively straightforward schema, I'd expect you to be able to join all four tables in a single SQL statement. If part of the chain is missing, the query would return no rows.

Or am I missing something?