ruby-on-rails - Rails 数据库默认值和 bool 字段的模型验证

Question

在 Rails 模型中，我有一个属性 is_subscriber ，当我构建一个 db 迁移以将此列添加到数据库时，我将默认值指定为 false:

t.boolean  "is_subscriber",   :default => false

我还在模型中指定了这个属性需要存在:

validates :is_subscriber, presence: true

那么为什么在创建模型实例时未指定此属性时会出现此错误？

2012-05-08T21:05:54+00:00 app[web.1]: ActiveRecord::RecordInvalid (Validation failed: Is subscriber can't be blank):

Answer 1

来自 here

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

或以 Rails3 方式

validates :field, :inclusion => {:in => [true, false]}