send e-mail to multiple users

I would echo Sean's remarks about using test databases to try things out.

I'm not entirely certain about the idea of learning another programming language though because Ninox is so much quicker and relatively simple because of the integration of the application structure and database - in other words there's a lot you don't have to write any code for.

One thing I would suggest is that you take  part in the weekly Ninox webinars - although you won't learn all that much each week, you can always ask questions and you'll normally pick up a few hard learned tips along the way. 

There is deifnitely discussion going on at these about creating more learning content and I think this will happen fairly soon - I am even considering doing a series of blog posts to follow on from the Relating to Relational Databases ones (part two hopefully in the next week) and the one I did about sending bul emails on Friday.