has_one：通过不提供build_association

Question

TimeLog既可以开票也可以不开票，而且发票包含许多时间日志。我们的数据库不能有空的外键，所以我们使用了一个连接模型。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

NoMethodError: undefined method `build_invoice' for #<TimeLog:0x4acd588>

是不是HAS_ONE应该让现有的build_association方法？

更新：

我做了对这个问题的一个样本回购：build_assocation_test。要看到问题，克隆回购，安装包，运行迁移（或加载架构），然后在铁轨控制台：

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？