使用named_scope进行加法链接

发布于 2024-07-30 15:11:10 字数 317 浏览 3 评论 0原文

有没有办法以附加方式组合范围？

如果我有范围

User.big_haired

，

User.plays_guitar

我可以打电话

User.big_haired.plays_guitar

联系所有留着大头发并弹吉他的用户。我可以写这个来吸引所有有大头发或弹吉他的用户吗？

我想我必须补充一点，我意识到您可以运行一组查询并将结果添加在一起。这就是我试图不做的事情。

原文

Is there a way to combine scopes in an additive fashion?

If I have the scopes

User.big_haired

and

User.plays_guitar

I can call

User.big_haired.plays_guitar

and get all the users who have big hair AND play guitar. Can I write this to get all users who have big hair OR play guitar?

I guess I have to add that I realize that you can run a set of queries and add the results together. That's what I'm trying not to do.

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雾里花 2024-08-06 15:11:10

所以你有：

class User < ActiveRecord::Base
  named_scope :big_haired, :conditions => {:hair => 'massive'}
  named_scope :plays_guitar, :conditions => {:plays => 'guitar'}
end

User.big_haired.plays_guitar => 很多用户。

我不知道有什么方法可以将两者混合在一起。也许只是混合数组：

@users = (User.big_haired + User.plays_guitar).uniq

So you have:

class User < ActiveRecord::Base
  named_scope :big_haired, :conditions => {:hair => 'massive'}
  named_scope :plays_guitar, :conditions => {:plays => 'guitar'}
end

User.big_haired.plays_guitar => Lots of users.

I am unaware of a method to mash the two together. Perhaps just blending the arrays:

@users = (User.big_haired + User.plays_guitar).uniq

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不乱于心 2024-08-06 15:11:10

尝试一下Searchlogic，它最近支持使用 OR 组合命名范围

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浪菊怪哟 2024-08-06 15:11:10

我刚刚在一些定义了named_scopes 的模型上尝试了这一点。如果您将这些条件组合起来，它会将这些条件组合在一起作为 AND 条件。所以...

User.big_haired.plays_guitar

将导致（显然是我的速记 SQL，而不是真正的 Rails 生成的东西）

SELECT * FROM users WHERE hair = 'massive' AND plays = 'guitar'

我不知道如何将它们组合为 OR 关系。当你考虑各种选择时，混合起来会非常复杂。我们一直链接named_scopes，它工作得很好（只要你希望它们AND在一起）。

为了执行 and 情况，我要么创建一个带有 OR 条件的特殊命名范围，要么使用联合来生成一个唯一的集合，如下所示：

User.big_haired | User.plays_guitar

I just tried this out on some of my models that have named_scopes defined. It will put the conditions together as an AND condition if you combine it. So...

User.big_haired.plays_guitar

will result in (obviously my shorthand SQL, not the real rails generated stuff)

SELECT * FROM users WHERE hair = 'massive' AND plays = 'guitar'

I don't know of a way to combine them as an OR relationship. That would be incredibly complex to mix in when you think about the various options. We chain named_scopes all the time, it works well (as long as you want them ANDed together).

To do the and case, I would either create a special named scope with the OR conditions built on, or use a union to produce a unique set like so: