Ruby on Rails ActiveRecord Validations Validating presence of an attribute
Example
This helper validates that the specified attributes are not empty.
class Person < ApplicationRecord
validates :name, presence: true
end
Person.create(name: "John").valid? # => true
Person.create(name: nil).valid? # => false
You can use the absence helper to validate that the specified attributes are absent. It uses the present? method to check for nil or empty values.
class Person < ApplicationRecord
validates :name, :login, :email, absence: true
end
Note:
In case the attribute is a boolean one, you cannot make use of the usual presence validation (the attribute would not be valid for a false value). You can get this done by using an inclusion validation:
validates :attribute, inclusion: [true, false]
