Rails：使用has_many：through建模直接数据

时间：2021-08-01 16:53:28

I have a pretty simple set of data requirements to do with pets and veterinarians.

我对宠物和兽医有一套非常简单的数据要求。

  • An owner can have many pets
  • 主人可以养很多宠物
  • A pet can have one owner
  • 宠物可以拥有一个主人
  • A pet can be treated by (belongs_to) many veterinarians
  • 宠物可以由（belongs_to）许多兽医治疗
  • A veterinarian can treat (have_many) pets
  • 兽医可以治疗（有很多）宠物

Owner and Veterinarian are both subclasses of User using STI.

所有者和兽医都是使用STI的用户的子类。

Here's some code:

这是一些代码：

class Owner < User
  has_many :pets
  has_many :veterinarians, :through => :pets
end

class Veterinarian < User
  attr_accessible :clinic_name

  has_many :pets
  has_many :owners, :through => :pets
end


class Pet < ActiveRecord::Base
  attr_accessible :name, :date_of_birth, :species, :breed, :gender, :neutered

  belongs_to :owner
  belongs_to :veterinarian
end

And here is the spec that is failing:

以下是失败的规范：

it "has various veterinarians" do
  o = Owner.make!(:email => 'owner1@gmail.com')
  v1 = Veterinarian.make!(:email => 'vet_1@gmail.com')
  v2 = Veterinarian.make!(:email => 'vet_2@gmail.com')
  p = Pet.make!(:name => 'fluffy')

  o.pets << p
  v1.pets << p
  v2.pets << p

  o.pets.should have(2).records
  o.veterinarians.should have(2).records
end

The make! stuff is to do with using machinist fixture replacement. It just factory creates the objects.

制作！与使用机械师夹具更换有关。它只是工厂创建对象。

The failure occurs on the last line. It turns out that o.veterinarians only has 1 record. I understand that a pet is not a join table in the traditional sense, inasmuch as I don't want to create a whole new pet each time I create a relationship between an owner and a veterinarian. Should I be using a schema more like Owner has_many Pets, Pet belongs_to :owner and Pet has_and_belongs_to_many Veterinarians?

失败发生在最后一行。事实证明，o.veterinarians只有1条记录。我知道宠物不是传统意义上的连接桌，因为每次我在主人和兽医之间建立关系时我都不想创造一个全新的宠物。我是否应该使用更像所有者has_many Pets，Pet belongs_to：owner和Pet has_and_belongs_to_many兽医？

Thanks!

谢谢！

1 个解决方案

#1

1  

You have to use a join table between the Pet and the Veterinarian. Let's call it Treatment:

您必须在宠物和兽医之间使用连接表。我们称之为治疗：

class Treatment < ...
...
  belongs_to :pet
  belongs_to :veterinarian
...
end

class Veterinarian < ...
...
  has_many :treatments
  has_many :pets, through: :treatments
...
end

class Pet < ...
...
  has_many :treatments
  has_many :veterinarians, through: :treatments
...
end

#1

1  

You have to use a join table between the Pet and the Veterinarian. Let's call it Treatment:

您必须在宠物和兽医之间使用连接表。我们称之为治疗：

class Treatment < ...
...
  belongs_to :pet
  belongs_to :veterinarian
...
end

class Veterinarian < ...
...
  has_many :treatments
  has_many :pets, through: :treatments
...
end

class Pet < ...
...
  has_many :treatments
  has_many :veterinarians, through: :treatments
...
end
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