identifies all roles
whose privileges the current user can use. This means there is
some chain of role grants from the current user to the role in
question. The current user itself is also an applicable role. The
set of applicable roles is generally used for permission checking.
|Name of the role to which this role membership was granted (can be the current user, or a different role in case of nested role memberships)
|Name of a role
if the grantee has the admin option on