Ruby associations without Rails

Question

In Rails it's very easy to do things like User.first.monkeys.first.uncle, etc.

How could I get at this awesomeness without Rails and without a database? I noticed there's ActiveModel, but as far as I can tell it doesn't have any support for associations.

I'd like to be able to do things like this:

foo = Foo.new

foo.bars
# => []

foo.add_bar(:a => 'a')
foo.bars
# => [#<Bar @attr={:a=>'a'}>]

foo.bars.first.bazs
# => []

foo.bars.first.add_baz(:b=>'b')
foo.bars.first.bazs
# => [#<Baz @attr={:b=>'b'}]

foo.bars.first.foo
# => [#<Foo>]

Thanks in advance.

Answer 1

Why not just use an in-memory database with ActiveRecord and SQLite? You don't need to import all of Rails just to use the ORM. You could also use an alternative like Sequel or DataMapper depending on your preferences.