SQL 2005 Permission Precedence
Never a simple answer...

For a direct DELETE, a user in both roles won't be able to DELETEDENY always has precedence when permissions are checked

For indirect via a stored procedure, the permissions may not be checked if both table and proc have the same owner. So both GRANT and DENY will be ignored. This is called "ownership chaining"

Personally, I don't really use DENY. Here's why:

In your case, you only need to GRANT DELETE to the Admin role. The Basic role needs neither DENY nor GRANT (but run REVOKE DELETE to remove the Basic DELETE permission)


The lack of a DELETE permission (by REVOKE) means a DELETE will fail for a Basic only user. DENY isn't needed to prevent this.
An Admin user (whether in both roles or not) has a GRANT so the DELETE will succeed. No DENY to block them