module DataMapper::Validations::ValidatesPresence

Public Instance Methods

validates_presence_of(*fields) click to toggle source

Validates that the specified attribute is present.

For most property types “being present” is the same as being “not blank” as determined by the attribute's blank? method. However, in the case of Boolean, “being present” means not nil; i.e. true or false.

@note

dm-core's support lib adds the blank? method to many classes,

@see lib/dm-core/support/blank.rb (dm-core) for more information.

@example Usage

require 'dm-validations'

class Page
  include DataMapper::Resource

  property :required_attribute, String
  property :another_required, String
  property :yet_again, String

  validates_presence_of :required_attribute
  validates_presence_of :another_required, :yet_again

  # a call to valid? will return false unless
  # all three attributes are !blank?
end
# File lib/dm-validations/validators/required_field_validator.rb, line 76
def validates_presence_of(*fields)
  validators.add(PresenceValidator, *fields)
end