Which of the following options in the Ruby on Rails MVC architecture handles the dynamic data and the classes with the database?

In the case of Rails application performance optimization, select all valid ways to do assets compilation:

What is the best way to get the current request URL in Rails?

How can a value be stored so that it's shared across an entire request (i.e. make it accessible in controllers, views and models)?

Which commands adds the data model info to the model file?

Which HTML template languages are supported by Ruby?

If a float is added to an integer, what is the class of the resulting number? i.e. 1.0 + 2

In order to enable locking on a table, which of the following columns is added?

Which is the best way to add a page-specific JavaScript code in a Rails 3 app? <%= f.radio_button :rating, 'positive', :onclick => '$('some_div').show();' %>

Which of the following is the correct syntax for an input field of radio buttons in form_for?

Which of the following is the correct way to rollback a migration?