Do I Need a DBA  if I have Registered a Corporation

(If you do business in a name other than the corporation's name, you need a DBA. 

 For example if you are a corporation doing  business as the corporate certificate name (xyz, inc),  you don't need a Ficticious business. 

However, if you xyz, inc doing business as "Rob 'em & Cheat 'em"  You need a dba under the corporate name.