Rails 孙子对象带有 :has_many, :through

发布于 2024-12-04 02:09:35 字数 508 浏览 2 评论 0原文

我的模式结构如下：

class Foo < ActiveRecord::Base
  has_many :foo_bars
  has_many :foo_bar_bazs, :through => :foo_bars
end


class FooBar < ActiveRecord::Base
  has_many :foo_bars
  belongs_to :foo_bar
end

Class FooBarBaz < ActiveRecord::Base
  belongs_to :foo_bar
end

我正在尝试对 Foo 模型进行选择 - 例如 Foo.find(:all)。 FooBar 和 FooBarBaz 在数据库中都有正确的外键列（分别为 foo_id 和 foo_bar_id）。那么当我访问祖父母对象（Foo）时，如何访问子对象和孙对象呢？

最后，我需要在三个嵌套循环中迭代 Foo 对象，然后遍历 Foobar 对象，然后遍历 FoobarBaz 对象。

原文

I have a schema structured as follows:

class Foo < ActiveRecord::Base
  has_many :foo_bars
  has_many :foo_bar_bazs, :through => :foo_bars
end


class FooBar < ActiveRecord::Base
  has_many :foo_bars
  belongs_to :foo_bar
end

Class FooBarBaz < ActiveRecord::Base
  belongs_to :foo_bar
end

I'm trying to do a select on the Foo model - like Foo.find(:all). Both FooBar and FooBarBaz have the correct foreign key column in the database (foo_id and foo_bar_id, respectively). So how do I access the child and grandchild objects when I access the grandparent object (Foo)?

In the end I need to be iterate through the Foo objects, then through the Foobar objects, then through the FoobarBaz objects, in three nested loops.

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风筝在阴天搁浅。 2024-12-11 02:09:35

首先，我将修改语法以匹配约定：

class Foo < ActiveRecord::Base
  has_many :foo_bars
  has_many :foo_bar_bazs, :through => :foo_bars
end


class FooBar < ActiveRecord::Base
  has_many :foo_bar_bazs
  belongs_to :foo_bar
end

Class FooBarBaz < ActiveRecord::Base
  belongs_to :pc_scene_item
end

现在我们有了对象：

Foo.find(:all, :include => [:foo_bars, :foo_bar_bazs])

现在，可以避免 :through，并且您可以执行以下操作：

foos = Foo.find(:all, :include => [{:foo_bars => [:foo_bar_bazs]}])

获取所有子项：

children = foos.collect{|f| f.foo_bars}.flatten.uniq

获取所有孙子项：

grandchildren = foos.collect{|f| f.foo_bars.collect{|b| b.foo_bar_bazs}}.flatten.uniq

First, I'd revise the syntax to match convention:

class Foo < ActiveRecord::Base
  has_many :foo_bars
  has_many :foo_bar_bazs, :through => :foo_bars
end


class FooBar < ActiveRecord::Base
  has_many :foo_bar_bazs
  belongs_to :foo_bar
end

Class FooBarBaz < ActiveRecord::Base
  belongs_to :pc_scene_item
end

Now that we have the objects:

Foo.find(:all, :include => [:foo_bars, :foo_bar_bazs])

Now, :through can be avoided, and you can do:

foos = Foo.find(:all, :include => [{:foo_bars => [:foo_bar_bazs]}])

To get all children:

children = foos.collect{|f| f.foo_bars}.flatten.uniq

To get all grandchildren:

grandchildren = foos.collect{|f| f.foo_bars.collect{|b| b.foo_bar_bazs}}.flatten.uniq

回复收藏 0 原文

沉溺在你眼里的海 2024-12-11 02:09:35

你不应该使用驼峰命名法来命名你的关联，而应该使用蛇形命名法：

class Foo < ActiveRecord::Base
  has_many :foo_bars
  has_many :foo_bar_bazs, :through => :foo_bars
end

class FooBar < ActiveRecord::Base
  has_many :foo_bar_bazs
  belongs_to :foo
end

class FooBarBaz < ActiveRecord::Base
  belongs_to :foo_bar
end

You shouldn't use camel case to name your associations, but snake case:

class Foo < ActiveRecord::Base
  has_many :foo_bars
  has_many :foo_bar_bazs, :through => :foo_bars
end

class FooBar < ActiveRecord::Base
  has_many :foo_bar_bazs
  belongs_to :foo
end

class FooBarBaz < ActiveRecord::Base
  belongs_to :foo_bar
end

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