How to use ActiveRecord in module?

Question

require 'active_record'

module Module1
    module Module2
        class Database
            ActiveRecord::Base.establish_connection(
                :adapter  => 'postgresql',
                :host     => 'db_url',
                :username => 'db_username',
                :password => 'db_password',
                :database => 'db_name'
            )


            class People < ActiveRecord::Base
            end
        end
    end
end

I can move the ActiveRecord establish connection bit into a an initialize function, and instantiate the class however, I still get a NoMethod error when I try to call the People class.

The goal is to use it outside of the module/class by doing something like the following:

db = Module1::Module2::Database
db.People.all.each do |Person|
  puts Person
end

Answer 1

The answer is to move into another module so it doesn't require instantiation, and it's not in a class:

require 'active_record'

module Module1
    module Module2
        module Database
            ActiveRecord::Base.logger = Logger.new(STDOUT)
            class People < ActiveRecord::Base
            end
        end
    end
end

Then to use it:

# get a configuration object like this similiar to how rails is configured
dbconfig = YAML::load(File.open('config/database.yaml'))
db.establish_connection(dbconfig["database1"])
db = Module1::Module2::Database::People
db.all.each do |x|
    puts x.created_at
end

# switch between profiles
db.establish_connection(dbconfig["database2"])
db = Module1::Module2::Database::People
db.all.each do |x|
    puts x.created_at
end

config/database.yaml should resemble this:

database1:
  adapter: <adapter_name>
  username: <username>
  password: <password>
  host: <host>
  database: <database_name>

This approach is "single threaded" in the sense that you can only be connected to one database at a time because ActiveRecord connections overwrite each other as you switch between them. So switch get your data and switch again.