与 Mongoid 的关联

发布于 2024-12-24 00:54:32 字数 1269 浏览 2 评论 0原文

我有三个简单的模型 - Car、Details 和 Details2。 Car 有很多 Details，Details 有很多 Details2。

使用 MySQL 和 ActiveRecord，我将设置如下关联：

class Car
  has_many :details
end


class Detail
   belongs_to :car
end

在视图中，我有一个汽车列表，我有：

<% @cars.each do |car| -%>
  <%=car.details.count%> #uninitialized constant Details
<% end %>

EDIT2： 这是我在 cars 表中的内容：

db.cars.find()
{ "_id" : ObjectId("4efe69716f85ce447a000054"), "name" : "bmw", "descr" : "asasgasga as gas gas ", "updated_at" : "Sat Dec 31 2011 02:46:25 GMT+0100 (CET)", "created_at" : "Sat Dec 31 2011 02:46:25 GMT+0100 (CET)" }

和 details：

db.details.find()
{ "_id" : ObjectId("4f01106d6f85ce6b850000b8"), "car_id" : ObjectId("4efe69716f85ce447a000054"), "name" : "20120102030325", "descr" : "dsg", "updated_at" : "Mon Jan 02 2012 03:03:25 GMT+0100 (CET)", "created_at" : "Mon Jan 02 2012 03:03:25 GMT+0100 (CET)" }

在 CarsController 中，我仅在此操作中拥有：

def index
  @cars = Car.all
end

这就是我所做的全部。

原文

I have three simple models - Car, Details and Details2.
Car have lot of Details and Details have lot of Details2.

With MySQL and ActiveRecord I will set the associations like:

class Car
  has_many :details
end


class Detail
   belongs_to :car
end

In the view, where I have a list of Car, I have:

<% @cars.each do |car| -%>
  <%=car.details.count%> #uninitialized constant Details
<% end %>

EDIT2:
This is what I have in cars table:

db.cars.find()
{ "_id" : ObjectId("4efe69716f85ce447a000054"), "name" : "bmw", "descr" : "asasgasga as gas gas ", "updated_at" : "Sat Dec 31 2011 02:46:25 GMT+0100 (CET)", "created_at" : "Sat Dec 31 2011 02:46:25 GMT+0100 (CET)" }

and details:

db.details.find()
{ "_id" : ObjectId("4f01106d6f85ce6b850000b8"), "car_id" : ObjectId("4efe69716f85ce447a000054"), "name" : "20120102030325", "descr" : "dsg", "updated_at" : "Mon Jan 02 2012 03:03:25 GMT+0100 (CET)", "created_at" : "Mon Jan 02 2012 03:03:25 GMT+0100 (CET)" }

And in CarsController I have in this action only:

def index
  @cars = Car.all
end

that's all what I do.

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遗忘曾经 2024-12-31 00:54:32

您可以重用从 ActiveRecord 中了解到的信息。 has_many 和 belongs_to 工作正常在 Mongoid 中很好。

但是您可以利用文档数据库（MongoDB 就是）并使用一些嵌入。为了使 embedded_in 正常工作，您必须在另一端安装 embeds_one 或 embeds_many。请参阅http://mongoid.org/docs/relations/embedded/1-1。 html

  class Person
    include Mongoid::Document
    embeds_one :name
  end

  class Name
    include Mongoid::Document
    field :vorname, type: String
    field :nachname, type: String
    embedded_in :person
  end

You can reuse what you know from ActiveRecord. has_many and belongs_to work just fine in Mongoid.

But you can take advantage of document databases (which MongoDB is) and use some embedding. For embedded_in to work correctly you have to have embeds_one or embeds_many on the other end. See http://mongoid.org/docs/relations/embedded/1-1.html

  class Person
    include Mongoid::Document
    embeds_one :name
  end

  class Name
    include Mongoid::Document
    field :vorname, type: String
    field :nachname, type: String
    embedded_in :person
  end

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