How to unassign a value?

I have a table similar to the following

id | name | address

both name and address are not nullable(this i achieve through attribute setters only and not by default)

When i create a new record without any default values what will be stored in the table?

If the value is null

-> if i store a value (say name="MyName", address="The address"). can i reset it back to null at if needed? I cannot assign null here since my setter wont allow.

In 开发者_JAVA百科short - can i unassign a value stored in a record's field using something like

my_object.name.delete

from my controller?

Thanks you

Update-the model setter

def name=(value)
  if name.nil? raise "Can't be nil" 
end

You can. But first, my assumptions:

1. I'm going to assume that you are using ActiveRecord and you have a model called MyModel in order to treat that table.
2. I'm going to assume that you used the proper way to make fields non-nullable, which is by using validations. If this is not the case, I strongly suggest that you reconsider using them.

Then you can do:

class MyModel < ActiveRecord::Base
  validates_pressence_of :name, :if => :check_name

  attr_writer :check_name
  def check_name # make it defalt to true
    @check_name = @check_name.nil? ? true : @check_name
  end
end

You can use it like this:

my_object.name = "Josh"
my_object.save # ok
my_object.name = ""
my_object.save # not ok
my_object.check_name = false
my_object.save # ok