Returning results from a loop dbvisualizer

I'm pretty new to DbVisualizer (v6.5.5) and have been trying to get even a basic loop to return some results. Just something I can build off of but no luck and I can't seem to find anything online that helps. This query executes successfully (no error) but doesn't show any results. What am I missing? Database is Oracle 11g.

--/
DECLARE
  a number(2);
   BEGIN
     FOR a in 1 .. 20 LOOP
     dbms_output.put_line('value of a: ' || a);
   END LOOP;
 END;
/

How can I get them to show up?

Solution

First I suggest you upgrade to the latest 9.1 version since 6.5.5 is very old.

Secondly, to take care of DBMS_OUTPUT calls you need the DbVisualizer Pro edition with support for this feature. If you don't have a license for DbVisualizer Pro, sign-up using v9.1 and in the Help->Evaluate Pro Edition.

Once DbVisualizer Pro 9.1 is running, there is a DBMS Output tab that will appear in the SQL Commander for your Oracle connection.

Hope this helps.