I’ll assume from your post that your are interested in GUI desktop apps
in Windows, specifically connected to a database file or database
Generally speaking, Ruby is used in the same places other “scripting”
languages (perl, python, etc) are used, such as back-end web development
(Ruby on Rails, Nitro, Camping, etc), command line apps (which are more
common in unix and OS X, but still exist in Windows ), and back-end
processes (services in Windows, or daemons in unices).
Ruby can be used to write desktop GUI applications too, as previous
posts have mentioned, however it isn’t, at this point, going to be like
writing something in VB, Java, or .net; yet.
Specifically on Windows, when writing a desktop GUI app, the most common
ways are to: write directly to Windows using the Win32 API, use a
framework such as .net’s WinForms (VB in the old days), or use a cross
platform framework such as Swing in Java, or QT, gtk, etc.
As is true with all languages, not only Ruby, if you want to create an
application that just runs on Windows without installing a framework,
you work directly with the Win32 API, which is very common in c and c++.
I’m not familiar with it, but there is a Win32api module in Ruby.
As for the .net and java environments, there are projects currently
being developed to get Ruby to run in those. This would be typically
the best approach, unless you are currently writing your own message
loops in c. The projects are JRuby, and Ruby.net (there are others as
You mentioned DAO (wow, that is old), which you are using probably to
connect to an Access or SQL Server database. In this regard, Ruby is
great, and has many tools for accessing a database, wether just a file
or a server. If you’re familiar with DAO, ADO, or ADO.net, you’ll feel
right at home in Ruby. Start your study by looking into DBI. Other
interesting areas to research are ActiveRecord, Og, and directly
connecting to a DB such as the mysql gem.
 Windows users who aren’t familiar with the command line often think
that the Command Line in Windows is DOS. Actually, the command line
(cmd.exe) is simply a way to work with the operating system, and run
applications without a graphical user interface. If you run an app in
the command line, it is still running in Windows, it just doesn’t have a
GUI. DOS is an entirely different OS (which you can still run inside
Windows by using Command.com, but there is rarely a need to)