如何管理与 Rails 的 n:n 关系？

发布于 2024-08-06 08:17:29 字数 481 浏览 2 评论 0原文

假设我有一家公司，有许多员工，每个员工可以拥有许多公司。

基本上我会有 :

class Employee < ActiveRecord::Base
  has_and_belongs_to_many :companies
end

然后

class Company < ActiveRecord::Base
  has_and_belongs_to_many :employees
end

我很困惑如何得到这样的东西：

名称以“John”开头的公司的所有员工
公司的所有员工首先按姓名排序，其次是电子邮件。

难道还有什么我不知道的魔法吗？该示例仅用于演示，如果可以帮助您更好地解释，请随意做出假设或更改它。

原文

Let's say I have a Company that has many Employees and each Employee can have many Companies.

Basically I will have :

class Employee < ActiveRecord::Base
  has_and_belongs_to_many :companies
end

and

class Company < ActiveRecord::Base
  has_and_belongs_to_many :employees
end

But then I'm confused about how I could get things like:

All the employees of a company with the name starting by "John"
All the employees of a company order by name first, email second.

Is there some magic I don't know about? The example is just here for the demo, feel free to make assumptions or change it if it helps you explain better.

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樱＆纷飞 2024-08-13 08:17:29

为了让所有以“John”开头的员工，您可以这样做（当然还有很多其他方法可以做到这一点，但无论如何）：

some_company.employees.find(:all, :conditions => "name LIKE 'John%'")

对于员工的排序，它甚至更漂亮：

class Company < ActiveRecord::Base
  has_and_belongs_to_many :employees, :order => "name, email"
end

您可以使用 ActiveRecord 做更多的事情。我建议您尝试阅读 http://guides.rubyonrails.org/ 或观看 http://railscasts.com/ 了解更多有关 RoR 之美的信息 =)

希望它有所帮助！

For getting all the employees starting with "John", you can do (of course there are many other ways to do it, but anyway):

some_company.employees.find(:all, :conditions => "name LIKE 'John%'")

For ordering of the employees it's even prettier:

class Company < ActiveRecord::Base
  has_and_belongs_to_many :employees, :order => "name, email"
end

There are a whole lot more you can do with ActiveRecord. I suggest that you try reading up on http://guides.rubyonrails.org/ or watch http://railscasts.com/ to learn more about the beauty of RoR =)

Hope it helps!

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