Question

我在Rails中很陌生，但是遇到了问题。像这样从YML文件加载数据的最佳方法是什么：

   projects:
 - title: 'family'
   todos:
    - text: 'Get some milk'
      isCompleted: false
    - text: 'Cook some bacon'
      isCompleted: true
    - text: 'Repair the front door'
      isCompleted: false
 - title: 'work'
   todos:
    - text: 'Call my boss'
      isCompleted: true
    - text: 'Finish my work tasks'
      isCompleted: true
    - text: 'Get fired'
      isCompleted: false
 - title: 'therest'
   todos:
    - text: 'Do something'
      isCompleted: false
    - text: 'Ask a question on stackoverflow'
      isCompleted: false

因此，我有两个模型-待办事项模型（文本和isCompleted字段）和项目模型（仅标题字段）。项目has_many待办事项。我试图这样做：

seed_file = Rails.root.join('db', 'seeds', 'seeds.yml')
config = YAML::load_file(seed_file)
Project.create!(config)

但是我有一个错误：

ActiveModel::UnknownAttributeError: unknown attribute 'projects' for Project.

我该如何解决？

Answer 1

class Project < ApplicationRecord
  has_many :todos
  accepts_nested_attributes_for :todos
end

Project.create!(title: 'family', 
                todos_attributes:[{text:'1',isCompleted:false}, 
                                 {text:'2',isCompleted:false},...])

如果必须使用YAML，则必须阅读YAML，然后将其转换为Rails可以用来创建实体的东西。将其放在您的种子文件中：

yaml_hash = YAML.load(File.read('db/your_yaml.yaml'))

rails_arr_of_hashes = yaml_hash['projects'].map{|p| {title: p['title'], todos_attributes: p['todos'] }

Project.create(rails_arr_of_hashes)

将您的YAML放入db / your_yaml.yaml，然后运行

rails db:seed

请记住将accepts_nested_attributes_for :todos添加到Project模型中。

祝您学习Rails好运：）

Answer 2

如聊天中所讨论的，您将需要使用以下内容：

config[:projects].each do |project|
  todos = project[:todos]
  project.delete(:todos)
  new_project = Project.create(project)
  todos.each do |todo|
    new_project.todos.create(todo)
  end
end

假定您的YML格式正确。

在Rails中以一对多关系将种子数据从YML加载到数据库

2 个答案: