Update method

I have a question on updating records. I have this User model that requires a password in order to save. In the database there is the password hash and salt so I don't save the password. However, when I retrieve a user record and try to update using the save function it would not update. I assume because the password attribute is automatically set to nil when retrieving a record.

Since I cannot use save, I tried the update method. For example if I type on the console

u=User.find(1) u.name="whatever" u.update

This worked but I realized that the update method is not part of the rails API. There are only four update type methods in ActiveRecord::Base, update(:id, attributes), update_all(updates, conditions=nil), update_attribute, and update_attributes.

So my questions are 1) Why does update (without any arguments) work since it is not part of the API documentation? 2) Why does update_attributes not work in updating my user record but update_attribute works for one field? 3) Do you know a good way if I want to update my User record if I want to update more than one field? I don't mind using the update method w/ o parameters but I wonder if it is deprecated.

Thanks. -Rich