Active Record - Rails 6，具有两个不相关模型使用的模型

Question

假设我正在rails 6中构建一个手表分类器系统。我有一个名为material的模型，material由手表主体和手链使用。

模型应该是这样的：

Material:
    description - text (gold, platinum, steel, silver etc)

Bracelet:
    style - text
    Material - has_many references (could be silver and rose gold etc)
    clasp - text
    etc

Watch
    brand - text
    Material - has_many references (case could be gold & white Gold etc)
    etc

正如您所看到的，手环和手表在一对多的情况下都依赖于材料，但是材料不关心或不需要知道手表或手环，所以belongs_to:不适合，也不适合多态关联

如何在rails 6中对此进行建模？那么迁移会是什么样子呢？

谢谢

Answer 1

如下所示：

class CreateMaterials < ActiveRecord::Migration[6.0]
  def change
    create_table :materials do |t|
      t.integer :description, default: 0

      t.timestamps
    end
  end
end

class Material < ApplicationRecord
  enum description: %i[gold, platinum, steel, silver] # etc

  has_and_belongs_to_many :watches
  has_and_belongs_to_many :bracelets
end





class CreateBracelets < ActiveRecord::Migration[6.0]
  def change
    create_table :bracelets do |t|
      t.text :style
      t.text :clasp
      # etc

      t.timestamps
    end
  end
end

class Bracelet < ApplicationRecord
  has_and_belongs_to_many :materials
end




class CreateWatches < ActiveRecord::Migration[6.0]
  def change
    create_table :watches do |t|
      t.text :brand
      # etc

      t.timestamps
    end
  end
end

class Watch < ApplicationRecord
  has_and_belongs_to_many :materials
end




class CreateMaterialsBracelets < ActiveRecord::Migration[6.0]
  def change
    create_table :materials_bracelets, id: false do |t|
      t.belongs_to :material, foreign_key: true
      t.belongs_to :bracelet, foreign_key: true
    end
  end
end

class CreateMaterialsWatches < ActiveRecord::Migration[6.0]
  def change
    create_table :materials_watches, id: false do |t|
      t.belongs_to :material, foreign_key: true
      t.belongs_to :watch, foreign_key: true
    end
  end
end

你觉得这个决定怎么样？如果有什么不对劲，那就说出来。