What is the difference between "has_many :through" and "has_and_belongs_to_many"?

The following methods skip validations, and will save the object to the database regardless of its validity?

Which of the following statements are correct about Types of Templates? (choose all that apply)

How do you permit nester attributes in Rails controllers for such model? class User has_one :profile accepts_nested_attributes_for :profile end

How is it possible to create combined unique index for two fields?

Which of these options for 'dependent' do not exist in Rails?

Which expression will not return a sum of array elements in Ruby on Rails?

Which column type is NOT supported by Active Record?

Which of these code blocks cannot be right?

What is the output of the following? $x = 10 puts defined? $X

When you've got a form, and when the user submits invalid data, you redirect back to the edit form. If you want to show a general error message (not tied to validation errors) to the user, you'd do which of the following?