instance method
validates_presence_of
Ruby on Rails 2.3.18
Since v2.2.3Signature
validates_presence_of(*attr_names)
Validates that the specified attributes are not blank (as defined by Object#blank?). Happens by default on save. Example:
class Person < ActiveRecord::Base validates_presence_of :first_name end
The first_name attribute must be in the object and it cannot be blank.
If you want to validate the presence of a boolean field (where the real values are true and false), you will want to use validates_inclusion_of :field_name, :in => [true, false].
This is due to the way Object#blank? handles boolean values: false.blank? # => true.
Configuration options:
-
message- A custom error message (default is: “can’t be blank”). -
on- Specifies when this validation is active (default is:save, other options:create,:update). -
if- Specifies a method, proc or string to call to determine if the validation should occur (e.g.:if => :allow_validation, or:if => Proc.new { |user| user.signup_step > 2 }). The method, proc or string should return or evaluate to a true or false value. -
unless- Specifies a method, proc or string to call to determine if the validation should not occur (e.g.:unless => :skip_validation, or:unless => Proc.new { |user| user.signup_step <= 2 }). The method, proc or string should return or evaluate to a true or false value.
Parameters
-
attr_namesrest
Source
# File activerecord/lib/active_record/validations.rb, line 591
def validates_presence_of(*attr_names)
configuration = { :on => :save }
configuration.update(attr_names.extract_options!)
# can't use validates_each here, because it cannot cope with nonexistent attributes,
# while errors.add_on_empty can
send(validation_method(configuration[:on]), configuration) do |record|
record.errors.add_on_blank(attr_names, configuration[:message])
end
end
Defined in activerecord/lib/active_record/validations.rb line 591
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Defined in ActiveRecord::Validations::ClassMethods