为什么我的DataMapper验证不起作用？

Question

此示例不会为我验证标题的存在：

require 'rubygems'
require 'dm-core'
require 'dm-migrations'
require 'dm-validations'

db_name = 'rvtest.sqlite'

DataMapper::Logger.new($stdout, :debug)
DataMapper.setup(:default, 'sqlite://' + Dir.pwd + '/' + db_name)

class Task
  include DataMapper::Resource
  property :id,         Serial
  property :title,      String

  validates_presence_of :title
end

DataMapper.finalize
DataMapper.auto_upgrade!

然而，这个确实：

require 'rubygems'
require 'dm-core'
require 'dm-migrations'
require 'dm-validations'

db_name = 'rvtest.sqlite'

DataMapper::Logger.new($stdout, :debug)
DataMapper.setup(:default, 'sqlite://' + Dir.pwd + '/' + db_name)

class Task
  include DataMapper::Resource
  property :id,         Serial
  property :title,      String, :required => true

end

DataMapper.finalize
DataMapper.auto_upgrade!

为什么这些工作方式不同？如果我进入irb，请求此文件并输入Task.new.save!，第一个返回true，第二个返回false。

Answer 1

保存！不会调用任何回调，这意味着它不会调用验证。尝试保存