如何根据模型中的方法过滤或查找模型？
我有一个控制器正在从联系人表中查找一组联系人。目前它看起来像这样：
@contacts = @campaign.contacts.find(:all, :order => "date_entered ASC")
contact.rb（模型）中的方法是这样的：
def status
return if statuses.empty?
a= statuses.find(:last).status << ' (' << statuses.find(:last).created_at.to_s(:long) << ')'
return a
end
在大多数情况下，如果“状态”中有一个值，我不再希望在视图中显示它。
现在，状态是多态的。这可能是一个愚蠢的想法，但我希望状态的概念适用于不同的模型：
class Status < ActiveRecord::Base
attr_accessible :statusable_id, :statusable_type, :status
belongs_to :statusable, :polymorphic => true
end
# == Schema Information
#
# Table name: statuses
#
# id :integer not null, primary key
# statusable_id :integer
# statusable_type :string(255)
# status :string(255)
# created_at :datetime
# updated_at :datetime
#
我假设如果我可以将该条件添加到 @contacts 实例，那就可以解决它。但我不知道如何在 .find 方法的控制器中编写该条件（如果这是正确的方法）。
谢谢。
I have a controller which is looking for a set of Contacts from the Contacts table. Currently it looks like this:
@contacts = @campaign.contacts.find(:all, :order => "date_entered ASC")
The method in the contact.rb (Model) is this:
def status
return if statuses.empty?
a= statuses.find(:last).status << ' (' << statuses.find(:last).created_at.to_s(:long) << ')'
return a
end
For the most part, if there is a value in the "status", I no longer want to display it in the view.
Right now, status is polymorphic. That might've been a dumb idea, but I wanted the concept of status to apply across different models:
class Status < ActiveRecord::Base
attr_accessible :statusable_id, :statusable_type, :status
belongs_to :statusable, :polymorphic => true
end
# == Schema Information
#
# Table name: statuses
#
# id :integer not null, primary key
# statusable_id :integer
# statusable_type :string(255)
# status :string(255)
# created_at :datetime
# updated_at :datetime
#
I am assuming that if I can add that condition to the @contacts instance, that would take care of it. But I don't know how to write that condition in the controller on the .find method (if that is the right way to do it).
thanks.
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我假设
contact has_many statuses。我不确定应用程序的其余部分，但从您上面给出的代码来看，您似乎只对最后一个状态感兴趣，因此您最好制作状态和属性而不是has_many 关联。
但是，假设对于其他一些要求，您确实需要 has_many 关联，在这种情况下，您所做的似乎是合理的。
I am assuming that
contact has_many statuses. I am not sure about the rest of the app , but from the code that you have given above , it seems that you are interested in only the last status , and thus you might be better off making status and attribute instead of ahas_manyassociation .However , assuming that for some other requirement you do need the has_many association , in that case what you have done seems reasonable .
为了扩展 NM 的答案，为什么不建立联系 has_onelatest_status 关系，然后使用 :join 选项查找呢？它记录在 Active Record Base 页面 http://api.rubyonrails.org/classes /ActiveRecord/Base.html，只需搜索：joins。
如果你搜索连接表，并且你已经将关系定义为最新状态，那么你就会得到你想要的，对吗？
To expand on NM's answer, just why not make a contact has_one latest_status relationship, and then find using the :join option? It's documented in the Active Record Base page at http://api.rubyonrails.org/classes/ActiveRecord/Base.html, just search for :joins.
If you search the joined table, and you've defined the relationship already to be the latest status, then you'd have what you want, right?