A. When a declaratory relief is sought, all persons shall be made parties who have or claim any interest which would be affected by the declaration, and no declaration shall prejudice the rights of persons not parties to the proceeding.

B. The venue of the action shall be established by existing statutes; provided, however, where the action involves an individual defendant, the venue shall be in the county of the defendant's residence or where the defendant may be served with summons. If the action involves two or more defendants who reside in different counties, the venue shall be in any county where any defendant resides or may be served with summons. Where the action has as a defendant the Department of Corrections, the Board of Corrections or any of the agents, officers or employees of the Department or Board, the venue shall be in the county of the official residence of the Department or Board.

C. In any proceeding which involves the validity of a municipal ordinance or regulation, the municipality shall be made a party, and shall be entitled to be heard, and if a statute or regulation is alleged to be unconstitutional, the Attorney General of the state shall also be served with a copy of the proceeding and be entitled to be heard.