Let's say you have a User model

class User < ActiveRecord::Base
end

Now to update the first_name and last_name of a user with id = 1, you can write the following code.

user = User.find(1)
user.update(first_name: 'Kashif', last_name: 'Liaqat')

Calling update will attempt to update the given attributes in a single transaction, returning true if successful and false if not.