找不到child_model(NameError)

Question

我无法确定为什么我在这里收到名称错误.我是DataMapper的新手,但尝试关联.任何帮助表示赞赏.

用户:

class User
  include DataMapper::Resource

  property :id,            Serial, :key => true
  property :first_name,    String
  property :last_name,     String
  property :company,       String
  property :city,          String
  property :country,       String
  property :mobile_number, Integer
  property :email_address, String
  property :shahash,       String
  property :isRegistered,  Boolean

  belongs_to :event, :required => true
end

DataMapper.auto_upgrade!

事件:

class Event
  include DataMapper::Resource

  property :id,          Serial, :key => true
  property :name,        String
  property :occuring,    DateTime

  has n, :user
end

DataMapper.auto_upgrade!

Answer 1

我认为问题是你DataMapper.auto_upgrade!在每个模型定义之后调用.当您在定义一个模型后调用它时,那里没有子模型.相反,您应该定义和/或要求所有模型,然后执行以下操作:

DataMapper.finalize      # set up all relationships properly
                         # and do a basic model sanity check
DataMapper.auto_upgrade! # create database table if it doesn't exist