Ruby on rails RoR多对多关联

我通过CategoriesSpecifications表建立了类别和规格模型以及多对多关联，如下所示：

create_table :categories_specifications, id: false do |t|
   t.belongs_to :specification, null: false
   t.belongs_to :category, null: false
   t.integer :status, null: false, default: 0
end

通过类别选择所有规格的最佳实践和最短方法是什么

@category = Category.first
@category.specifications # this is the shortest way to select all specifications via Category

当然，请确保在模型中声明关联：

class Category < ActiveRecord::Base
  has_many :categories_specifications
  has_many :specifications, through: :categories_specifications
end

class Specification < ActiveRecord::Base
  has_many :categories_specifications
  has_many :categories, through: :categories_specifications
end

class CategoriesSpecification < ActiveRecord::Base
  belongs_to :category
  belongs_to :specification
end

类别

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推荐阅读：

假设您有以下内容：

class Category < ActiveRecord::Base
  has_many :specifications
  has_many :categories, :through => :categories_specifications
end

class CategoriesSpecification < ActiveRecord::Base
  belongs_to :category
  belongs_to :specification
end

class Specification < ActiveRecord::Base
  has_many :categories_specifications
  has_many :categories, :through => :categories_specifications
end

Category.find(1).specifications