System roles are built-in roles that are automatically created in each
        new database.
System roles:
- Cannot be dropped.
 
- Cannot have their default underlying system privileges modified or revoked.
 
- Can have additional roles and system privileges granted to (or
                    revoked from).
 
- Cannot be granted with administrative rights (WITH ADMIN OPTION or WITH ADMIN
                    ONLY OPTION clauses). 
 
- Have no a password assigned, so users cannot connect to the
                    database as a grantable system role.
 
- Do not own objects, except for the SYS, dbo, and rs_systabgroup
                    role.