我对ActiveRecord关联来说相当新鲜.我正在绘制一个应用程序,用于跟踪在一组用户之间谁欠彼此的钱.费用模型和用户模型似乎是自然选择,我不知道如何定义两者之间的关系.例如,我想跟踪债权人(“所有者”)和每笔费用的债务人,但这只是两个外键返回给用户.此外,每个用户可以拥有多个费用(作为债权人和债务人)我迄今为止对于协会的最好猜测是：
class Expense
# belongs_to or has_one here?
# Not sure about class => User Syntax:
# need to alias to foreign keys that reference the same model
belongs_to :creditor,:class => User
belongs_to :debtor,:class => User
class User
# has_many expenses defines a creditor relationship (user owns expense)
# how to define debtor relationship? (belongs_to...?)
has_and_belongs_to_many :expenses
我已经阅读了关于协会的Rails指南,但是在外键和连接表上我仍然相当失落.任何输入都非常感激！
解决方法
所以这绝对不是一个关于多对多关系的has_and_belongs_to_many.你只需要使用几个has_many关系.我认为应该最终看起来像这样：
编辑：哎哟,我很抱歉,有一点对不起,让我有另一个去：
class Expense # make sure expense table has 'creditor_id' and 'debtor_id' rows belongs_to :creditor,:class_name => "User",:foreign_key => :creditor_id belongs_to :debtor,:foreign_key => :debtor_id class User has_many :debts,:class_name => "Expense",:foreign_key => :debtor_id has_many :credits,:foreign_key => :creditor_id
