Ruby on rails 棘手的Rails 4 ActiveRecord继承

我创建了几个模型，如下所示。 基本模型是TransactionType和TransactionItem ExpenseType和IncomeType派生自TransactionType。 费用和收入来自TransactionItem

class TransactionType < ActiveRecord::Base
  scope :expense_types,  -> { where(tran_type: 'ExpenseType') }
  scope :income_types,   -> { where(tran_type: 'IncomeType') }
  self.inheritance_column = "tran_type"
  validates :name, uniqueness: true
end

class ExpenseType < TransactionType
end

class IncomeType < TransactionType
end

class TransactionItem < ActiveRecord::Base
validates :note, length: { in: 2..255 }
end

class Expense < TransactionItem
belongs_to :expense_type
validates :expense_type, presence: true
end

class Income < TransactionItem
belongs_to :income_type
validates :income_type, presence: true
end

如果有人能分享你解决这个问题的想法，那就太好了

谢谢，

---

Masc

如果费用属于ExpenseType，则费用表需要一个整数属性Expense\u type\u id

您可以将其添加到

 rails g migration AddExpenseTypeToExpense expense_type_id:integer

然后

rakedb:migrate

---

这同样适用于收入和收入类型

在

费用

表上是否有

费用类型id

列？这对于单表继承是否正确？

 rails g migration AddExpenseTypeToExpense expense_type_id:integer