Valid options
are :save, :create, and :update. The default value is :save.
validates_length_of(:first_name, :maximum => 35, :on => :create)
The :allow_nil option, if true, specifies that that the validation should be skipped if the
attribute is nil:
validates_length_of(:first_name, :maximum => 35, :allow_nil => true)
The :if option specifies a method, proc, or string that is called in order to determine
whether the validation should occur at all:
validates_length_of(:first_name, :maximum => 35, :if => :check_name)
validates_length_of(:first_name, :maximum => 35, :if => "check_name")
validates_length_of(:first_name,
:maximum => 35,
:if => Proc.new {|a| a.create_step == 2 })
For more information regarding validations, see Chapter 4.
validates_numericality_of(*attribute_names)
This method adds errors to the specified attributes if the value of the attribute is not numeric.
By default, this is done by attempting to convert it to a float with Kernel.Float, but this can be
overridden with the :only_integer options.
APPENDIX ?– ACTIVE RECORD METHODS IN DETAIL 263
class Account < ActiveRecord::Base
validates_numericality_of :value
end
In addition to the attributes to validate, this method takes the configuration options of
:only_integer, :on, :message, :allow_nil, and :if.
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