Which of the following methods is used to check whether an object is valid or invalid?

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

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

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();' %>

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

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

Which HTML template languages are supported by Ruby?

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

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)?

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

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