Question

TimeLog可以是开票还是不开票，而发票包含许多TimeLog。我们的数据库不能有可空的外键，所以我们使用的是连接模型。代码：

class TimeLog < ActiveRecord::Base
  has_one :invoices_time_logs
  has_one :invoice, through: :invoices_time_logs
end

class Invoice < ActiveRecord::Base
  has_many :invoices_time_logss
  has_many :time_logs, through: :invoices_time_logss
end

class InvoicesTimeLogs
  belongs_to :invoice
  belongs_to :time_log
end

Invoice.first.time_logs.build工作正常，但TimeLog.first.build_invoice给出了

NoMethodError：未定义的方法`build_invoice'for ＃＆LT; TimeLog：0x4acd588＆GT;

是不是has_one应该使build_association方法可用？

更新

我为这个问题制作了一个样本回购：build_assocation_test。要查看问题，请克隆存储库，安装捆绑包，运行迁移（或加载架构），然后在rails控制台中：

Invoice.create
Invoice.first.time_logs.build
TimeLog.create
TimeLog.first.build_invoice

Answer 1

我相信你有一个错字。

class Invoice < ActiveRecord::Base
  has_many :invoices_time_logss
  has_many :time_logs, through: :invoices_time_logss
end

应该是......

class Invoice < ActiveRecord::Base
  has_many :invoices_time_logs
  has_many :time_logs, through: :invoices_time_logs
end

没有

has_one：through不提供build_association

1 个答案: