::Base part meaning in ActiveRecord::Base

Question

What does ::Base part mean in Person < ActiveRecord::Base class declaration? I'm new to ruby and from what I've gathered so far, Person < ActiveRecord should be used. Thank you.

Answer 1

in Ruby, :: accesses static class or module constants. ActiveRecord::Base indicates that the ActiveRecord class or module has a static inner class called Base that you're extending.

Edit: as Mike points out, in this case ActiveRecord is a module...

Answer 2

::Base is a class in module ActiveRecord. One of the things modules do is provide namespacing in Ruby. In Ruby you don't inherit from a module but you can mix it in using the include statement.

May I suggest picking up the Pickaxe book or reading Why's (Poignant) Guide to Ruby.