Where to put code?

I have a set of methods that use AR objects to query the database and
use the results, in combination with the application of some simple
business rules (e.g., if-else statements + return values), to compute
values for display in a view.

My question is, generally, where is the appropriate place to put such
code (not in the view!)?

(1) The view-specific helper
(2) The model
(3) The controller


If it is very view specific, you can put them in a view helper.

If these methods are needed in almost all the controllers then you can
them in a superclass. Otherwise put them in a helper module and mix it
the controllers that requires it. Think about your application
and use your judgement. Instead of speculating, you could refactor it

I would also separate the business rule logic code from the data
manipulation code. This will allow code reuse.