ruby - DataMapper 一对多删除失败

Question

class Alpha
  include DataMapper::Resource
  property :id,   Serial
  property :name, String
  has n, :betas
end

class Beta
  include DataMapper::Resource
  property :id,   Serial
  property :name, String
  belongs_to :alpha
end

# Create an Alpha with two Betas
@alpha = Alpha.new(:name => 'A')
@alpha.betas << Beta.new(:name => 'B')
@alpha.betas << Beta.new(:name => 'C')
@alpha.save

puts @alpha.betas.inspect
puts "Destroyed? #{@alpha.betas.first.destroy}"
puts @alpha.betas.inspect

出于某种原因，DataMapper 没有删除关联的 Beta 对象。

这是一个错误还是我遗漏了什么？

一个完整的例子在这个要点中 https://gist.github.com/2219479

编辑:

答案是销毁Beta后重新加载Alpha对象

puts @alpha.betas.inspect
puts "Destroyed? #{@alpha.betas.first.destroy}"
puts @alpha.betas.reload
puts @alpha.betas.inspect

Answer 1

从已编辑的问题正文中复制答案，以便从“未回答”过滤器中删除此问题:

The answer is to reload the Alpha object after destroying the Beta

puts @alpha.betas.inspect
puts "Destroyed? #{@alpha.betas.first.destroy}"
puts @alpha.betas.reload
puts @alpha.betas.inspect

~ 根据 Craig552uk 回答