procedure dup_rec(<p_master_key> in <master_key_type>)
is
  <v_new_key> <master_key_type>;
begin
  -- create a master
  INSERT INTO <master_table>(<columns>)
  SELECT <columns>
  FROM   <master_table>
  WHERE  <master_key> = <p_master_key>
  RETURNING <new_key> INTO <v_new_key>;
  
  
  -- create details
  INSERT INTO <detail_table>(<columns>,...., <master_key>)
  SELECT <columns>,.....,<v_new_key>
  FROM   <detail_table>
  WHERE  <master_key> = <p_master_key>;
EXCEPTION
  <your_exception_handling>
end dup_rec;